CN109881066A - High-toughness heat-resistant Mg-Gd alloy and preparation method thereof suitable for low pressure casting - Google Patents

Abstract

The high-toughness heat-resistant Mg-Gd alloy and preparation method thereof that the invention discloses a kind of suitable for low pressure casting, the alloy composition mass percentage content are as follows: 4.0~8.0%Gd, 1.2~4.8%Zn, 0.5~1.2%Al, 0.1~0.3%Mn, 0.01~0.08%M, surplus is Mg and other inevitable impurity, wherein M is Ti, at least one of B element.For high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting of the invention after the heat treatment of low pressure casting, second level solution treatment and artificial aging, room temperature tensile intensity is 280MPa or more, and elongation percentage is 16% or more；Drawing by high temperature tensile strength is 190MPa or more at 200 DEG C, and elongation percentage is 16% or more, meets the high demand that aerospace, military project, automobile and other industries develop lightweight.

Description

High-toughness heat-resistant Mg-Gd alloy and preparation method thereof suitable for low pressure casting

Technical field

The invention belongs to industrial magnesium alloy and its manufacturing fields, and in particular to a kind of height suitable for low pressure casting is tough resistance to Hot Mg-Gd alloy and preparation method thereof.

Background technique

For magnesium alloy as most light engineering metal material (density of magnesium is 2/3, the 1/4 of steel of aluminium), specific strength is obvious Higher than aluminium alloy and steel, although specific stiffness is suitable with aluminium alloy and steel, it is much higher than engineering plastics, while there is good casting Property, the series of advantages such as machinability is good, thermal conductivity is good, damping and amortization and electromagnetic shielding capability are strong and are easily recycled, navigating The fields such as sky, space flight, automobile, electronics and defence and military have a wide range of applications.Magnesium alloy becomes substitution aluminium alloy, steel With engineering plastics to realize light-weighted ideal material, wherein it is aluminium alloy that it is maximum, which to substitute potentiality,.Cast aluminium alloy gold has must The toughness and tenacity and thermal stability wanted are widely used for production engine cylinder body and the parts such as cylinder cap and wheel hub at present, represent Alloy be A354, A356 and A380.If magnesium alloy replaces cast aluminium alloy gold, it must have equivalent toughness and tenacity, and It is inexpensive, be easy to cast.Low pressure casting is that dry compressed air or inert gas are passed through in the crucible of sealing, by means of effect In the pressure on metal bath surface, liquid alloy is passed through into running channel along stalk from bottom to top and is smoothly pressed into metal mold or sand mold etc. Casting mold type chamber, and solidification obtains the casting method of casting under pressure.With the alloy die cast technique phase generallyd use at present Compare, low pressure casting is the method for the large-scale complex-shaped high-integrity casting of production.

Earliest, the Atomic radiuses difference of main alloy element aluminium and magnesium is larger while in magnesium for the application of Mg-Al class magnesium alloy In have biggish solid solubility, play solution strengthening and precipitation strength in the alloy.Find that a small amount of Mn is significant in nineteen twenty-five After the corrosion resistance for improving Mg-Al-Zn system magnesium alloy, AZ (such as AZ91) and AM system magnesium alloy (such as AM60, AM50) develop into mesh Preceding most widely used commercialization magnesium alloy.However the high temperature creep property of AZ and AM magnesium alloy is very poor, it is lower than Aluminium Alloys in Common Use An order of magnitude is more, and the tensile strength when temperature is higher than 150 DEG C reduces rapidly, and reason is during high-temerature creep Mg of the oversaturated α-Mg matrix in grain boundaries₁₇Al₁₂Mutually discontinuous precipitation.By the way that alloying element is added to improve precipitated phase The heat resistance of characteristic (crystal structure, form and thermal stability) Lai Tigao Mg-Al alloy, but its room temperature and mechanical behavior under high temperature It is still unable to reach the level of cast aluminium alloy gold, seriously limits its application development.

Zinc Zn is alloying element important in magnesium alloy, and the maximum solid solution degree in Mg is up to 6.2wt%, can play solid solution Strengthen and ageing strengthening acts on.Typical Mg-Zn series cast magnesium alloy includes ZK51A and ZK60A, deforming alloy include ZK21A, ZK31, ZK40A, ZK60A and ZK61 etc..Increase with Zn content, the tensile strength and yield strength of alloy improve, but it is had no progeny Elongation reduces, and casting character, process plastic and welding performance deteriorate, and especially because freezing range is wide, (such as ZK60's is solidifying Gu section is up to 265 DEG C, Journal of Materials Science 45 (14) (2010) 3797~3803.) lead to hot tearing It is inclined to extremely serious, it is impossible to be used in die casting.

Rare earth element is all two to the Grain Refinement Effect of magnesium alloy to the beneficial effect and zirconium of magnesium alloy strength performance The discovery of tenth century the '30s, EK31 becomes in Mg-Zr class and develops into earliest in Mg-RE-Zr system (EK30, EK31, EK41) The high temperature cast magnesium alloy of function.Magnesium-rare earth alloy based on rare earth RE element has excellent aging hardening effect, a variety of with RE Novel magnesium alloy for main added elements is successively developed, such as WE54, WE43 alloy of Mg-Y system.Chinese invention patent 201410564817.1 (high thermal conductivities can die casting Mg-Y-Zr system complex magnesium alloy and preparation method thereof) report a kind of high thermal conductivity pressure Corrosion-resistant magnesium alloy is cast, the content that the component content of the magnesium alloy is Y is 1.5~4wt.%, the content of Mn is 0.001~ The content of 1wt.%, Zn are 0.001~2wt.%, and the content of Ca is 0.001~1wt.%, the content of Zr is 0.4~ 0.8wt.%, remaining is Mg；Since the addition of the Ca element in the alloy increased dramatically the solidification temperature range of alloy, increase Hot cracking tendency, die casting ingot casting tensile strength is only 140~190MPa.

The solid solubility (25wt%) of heavy rare earth element Gd in the magnesium alloy is very high, there is strong solution strengthening and ageing strengthening Effect, addition Gd can greatly improve the compactness of magnesium alloy, casting character, three warm (low temperature, room temperature and high temperature) performances, resist it is compacted Denaturation energy and corrosion resistance.It is found that early in researcher in 1974, by extruding, quenched and ageing treatment Mg- 15wt%Gd alloy is in high temperature and low temperature tensile strength all with higher.Although high Gd content leads to the density and cost of alloy Increase, but researcher is dedicated to keeping the magnesium alloy containing gadolinium by coordinating addition alloy element such as Sc, Mn, Nd, Y, Zr Mechanical property advantage reduces negative effect to the greatest extent, has developed some promising polynary magnesium alloys containing gadolinium, such as Mg-Gd-Y- Mn, Mg-Gd-Y-Zr, Mg-Gd-Nd-Zr and Mg-Gd-Sc-Mn etc..

Cheap Zn is added in Mg-Gd alloy, not only the Precipitation group for regulating and controlling the alloy system is woven with more significant Effect, and a variety of hardening constituents can be formed under the conditions of different Zn/Gd ratios: when mass ratio >=2.49 Zn/Gd in alloy Icosahedral quasicrystal body structure I phase (Mg easy to form when (atomic ratio >=6.0)₃Zn₆Gd)；When in alloy Zn/Gd mass ratio between Face-centred cubic structure W phase (Mg easy to form when (atomic ratio is between 1.5 and 6.0) between 0.62 and 2.49₃Zn₃Gd₂) and I phase；When Zn/Gd mass ratio W phase easy to form and long period when (atomic ratio is between 1.0 and 1.5) between 0.42 and 0.62 in alloy Stacking order structure LPSO phase (Mg₁₂ZnGd)；It is easy to form when mass ratio≤0.42 Zn/Gd (atomic ratio≤1.0) in alloy LPSO phase (Materials Science and Engineering:A 695 (2017) 135~143).A variety of Mg-Gd-Zn are strong Change the room temperature intensity and high-temperature behavior that mutually can be further improved magnesium alloy, Chinese invention patent 201610056992.9 is (a kind of More nanometers of phase composite strengthening magnesium alloys and preparation method thereof) report more nanometers of phase complex intensifyings enhancing wrought magnesium alloy, Ingredient is Mg-Gd-Zn alloy, wherein 10~25wt% of Gd content, Zn 1~5wt% of content, surplus Mg, wherein the quality of Gd The mass percentage difference of percentage composition and Zn are not less than 8.Preparation method is by classification extruding and multistage heat treatment work Skill obtains a kind of deformed magnesium alloy material of excellent in mechanical performance, and the heat treatment temperature section narrated is 200~550 DEG C, wherein 520~550 DEG C of solid solution temperature section, soaking time are 5~15h；450~520 DEG C for the treatment of temperature section is precipitated in high-temperature-phase, Soaking time is 10~120h；200~350 DEG C for the treatment of temperature section is precipitated in low-temperature phase, and soaking time is 15~100h.Middle promulgated by the State Council Bright patent 201310105667.3 (biodegradable Mg-Gd-Zn-Ag-Zr system magnesium alloy and preparation method thereof) reports one kind Biodegradable Mg-Gd-Zn-Ag-Zr system magnesium alloy and preparation method thereof, wherein the alloy is made of Gd, Zn, Ag, Zr and Mg, The weight percentage of each component are as follows: Gd 5~10%, Zn 0.5~3%, Ag 0.1~1%, Zr 0.1~1%, surplus are Mg.The preparation method of the alloy is the following steps are included: " (1) melting: the following raw material is added in smelting furnace and carries out melting: Gd is adopted With Mg-Gd intermediate alloy, Zn uses pure zinc, and Ag uses fine silver, and Zr uses Mg-Zr intermediate alloy, and the Mg of surplus uses pure magnesium；On Raw material is stated under protective gas after melting, is cast as Mg-Gd-Zn-Ag-Zr system magnesium alloy ingot；(2) Homogenization Treatments: The Mg-Gd-Zn-Ag-Zr system magnesium alloy ingot that step (1) obtains is kept the temperature 6~24 hours at 480~550 DEG C；It (3) will be equal The Mg-Gd-Zn-Ag-Zr system magnesium alloy that homogenizes that treated is squeezed or is rolled change after keeping the temperature 1~3 hour at 250~350 DEG C Shape." foregoing invention are as follows: rare earth Gd content is too high to cause its density excessive, while expensive rare earth Price causes the invention to be difficult industrially to be applied on a large scale.There is no the elements such as Al and Mn to refine crystal grain, although can lead to It crosses Ag and Zr is refined, but coarse grains under the conditions of conventional coagulation, and Mg-Gd-Zn precipitated phase is usually in coarse Reticular structure, be degrading its mechanical property, it is necessary to pass through thermal deformation or heat treatment solid solution and timeliness adjust precipitate size To play the effect of its hardening constituent, current this kind of Mg-Gd-Zn alloy is typically limited to gravitational casting and heat processing technique, and It is necessarily required to complicated heat treatment process, has not been used in the report of die casting application.

Mg-Gd-Zn alloy is usually added into Zr as grain refining element, to refine its coarse microstructure.At present Report adds Zr mode to have halogen, Zn-Zr intermediate alloy and Mg-Zr intermediate alloy of sponge Zr, Zr etc., wherein among Mg-Zr Alloy have the advantages that it is easy to use, be mingled with less and good in refining effect, be the major way for being currently fed Zr.But still exist very much Problem: firstly, the preparation process of Mg-Zr intermediate alloy is complicated, energy consumption is high, lead to that it is expensive, therefore using among Mg-Zr Alloy refinement crystal grain can improve product cost；Secondly, the chemical activity of Zr is strong, it is easy at high temperature and atmosphere, furnace gas reacts, when When using steel crucibles, when melt temperature is higher than 750 DEG C, Zr be easy and crucible in Fe reaction, generate between stable metal Compound Fe₂Zr, the loss that these result in Zr are high；Many Zr in Mg-Zr intermediate alloy are with large scale simple substance Zr particle Form exist, since the fusing point of Zr is high (1852 DEG C), Zr particle is difficult to dissolve in melt, in addition the density of Zr is much larger than magnesium (density of Zr is 6.52g/cm to the density of melt³, the density of pure Serum Magnesium is 1.58g/cm³), it is easy to be deposited to crucible bottom, Cause the recovery rate of Zr low.

Summary of the invention

The present invention is unable to reach the casting aluminium such as A380 to solve existing cast magnesium alloy because of obdurability, heat resistance deficiency It is tough resistance to provide a kind of height suitable for low pressure casting for the performance of alloy, the professional problem for causing its application to be extremely restricted Hot Mg-Gd alloy and preparation method thereof, the alloy after low pressure casting is heat-treated, the room temperature tensile intensity of alloy be 280MPa with On, elongation percentage is 16% or more；Drawing by high temperature tensile strength is 190MPa or more at 200 DEG C, and elongation percentage is 16% or more.

In order to solve the above-mentioned technical problem, the present invention adopts the following technical solutions:

In a first aspect, the present invention relates to a kind of high-toughness heat-resistant Mg-Gd alloys suitable for low pressure casting, including press quality hundred The following element of score meter: 4.0~8.0%Gd, 1.2~4.8%Zn, 0.5~1.2%Al, 0.1~0.3%Mn, 0.01~ 0.08%M, surplus are Mg and other inevitable impurity, wherein M is at least one of Ti and B element.

Preferably, Zn/Gd mass ratio is 0.2~0.6:1.

Preferably, (Zn+Al)/Gd mass ratio is 0.3~0.7:1.

Preferably, to account for the percent by weight of the Mg-Gd alloy gross weight, when the M is the composite component of Ti and B, The mass fraction of Ti is 0.01~0.08%, the mass fraction of B is 0.01~0.08%.

Compared with prior art, the wound of the high-toughness heat-resistant Mg-Gd alloy provided by the invention suitable for low pressure casting One of new thought are as follows: alloy design forms ternary Mg-Gd-Zn using cheap Zn element and rare-earth Gd element and matrix Mg element Hardening constituent.Especially in the range of Zn/Gd mass ratio 0.2~0.6, on the one hand alloy of the present invention primarily forms long period stacking Ordered structure LPSO phase (Mg₁₂) and face-centred cubic structure W phase (Mg ZnGd₃Zn₃Gd₂), it is high-melting-point phase, it is strong with binary Mg-Gd Change is compared, and high-temperature stable of the ternary hardening constituent in magnesium matrix is more preferable, and the performance as caused by precipitation strength phased soln is avoided to drop It is low, the room-temperature mechanical property and high-temperature behavior of the high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting are effectively enhanced, especially It is that room-temperature yield strength doubles；On the other hand, the present invention overcomes traditional Mg-Zn-Gd alloys because of excessively high Zn content Lead to that freezing range is excessive and is also easy to produce thermal fragmentation defect, not can guarantee the toughness and tenacity and die casting performance of alloy.

The two of the innovative idea of high-toughness heat-resistant Mg-Gd alloy provided by the invention suitable for low pressure casting are as follows: Mg-Gd- Zn alloy precipitated phase under the conditions of conventional coagulation is usually in coarse reticular structure, is degrading its mechanical property, it is often necessary to logical Overheating deforming or heat treatment solid solution and timeliness adjust precipitate size to play the effect of its hardening constituent.Such alloy usually adds Enter Zr as grain refining element, Al, Mn and rare-earth Gd alloying element, these elements and Zr are contained in alloying element of the invention In conjunction with formation Al₃The compounds such as Zr and being deposited to crucible bottom makes zirconium not play Grain Refinement Effect.On the other hand, studies have shown that The thermal structure stability for adding Mg-Gd~Zn alloy of Zr refinement is poor, and in 550 DEG C of heat preservations, crystal grain is sharply roughened, and leads to height Warm nature can be greatly lowered.0.5~1.2%Al that low melt is added in alloy of the invention substitutes Zr, forms the Gao Rong of disperse Point Al₂Gd phase has not only refined the tissue of alloy, but also the high-temperature stable of Magnesium Alloy is ensured with high-temperature-phases such as LPSO Property.Al plays composite crystal grain fining together with a small amount of Ti and B simultaneously, has further refined alloy structure, has improved alloy Obdurability.A small amount of Mn is added in alloying element of the invention, can not only promote the formation of LPSO phase, improves the height of alloy Temperature stability, and improve the corrosion resistance of magnesium alloy.

The three of the innovative idea of high-toughness heat-resistant Mg-Gd alloy provided by the invention suitable for low pressure casting are as follows: the present invention Alloy in limit Zn/Gd mass ratio 0.2~0.6 and (Zn+Al)/Gd mass ratio as 0.3~0.7, guarantee the solidification of alloy Section is small, to overcome the hot cracking tendency in the press casting procedure of Mg-Gd-Zn alloy, improves the die-casting process performance of alloy.

Second aspect, the present invention relates to a kind of preparation method of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting, packets Include following steps:

S1, technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot, Mg-Gd intermediate alloy and Mg-Mn intermediate alloy are removed Oxide layer and dry be preheated to 180-200 DEG C；By the ingredient and stoichiometric ratio of above-mentioned Mg-Gd alloy, required raw material is calculated Dosage；

S2, by the technical pure magnesium ingot for accounting for crucible height 20-25% 675-685 DEG C, be passed through protective gas under conditions of it is molten Change；

S3, after the magnesium ingot all fusing, be warming up to 700~710 DEG C, by the pure zinc, Mg-Gd intermediate alloy and 2~4 additions of Mg-Mn intermediate alloy point, keep temperature constant at 700~710 DEG C, and stirring is extremely melted, and keeps the temperature 30-40 points Clock；

40~60 minutes before S4, low pressure casting, it is warming up to 730-740 DEG C, the aluminium ingot, Al-M intermediate alloy is added, is melted Change, refining, is warming up to 750~760 DEG C of heat preservations and stands 10~20 minutes, obtain magnesium alloy fused mass；

S5, the magnesium alloy fused mass is cooled to 720~740 DEG C, skims surface scum, preheating sand mold type molds temperature to 25 ~150 DEG C or metal type dies temperature are to 180~250 DEG C；In low pressure casting process, the pressure for rising the liquid stage is uniformly increased to 0.02~0.05MPa, pressing time control in 5~8s, and the pressure for filling the type stage is uniformly increased to 0.07-0.08MPa, molten metal Be full of casting mold type chamber under stress, the pressure of pressurization stages is uniformly increased to 0.1-0.15MPa, pressing time control 10~ The dwell time control of 15s, packing stage obtain Mg-Gd casting alloy low pressure casting after 200~300s, release；

S6, second level solution treatment, artificial aging processing are successively carried out to the Mg-Gd casting alloy low pressure casting, obtain The high-toughness heat-resistant Mg-Gd alloy.

Preferably, the Mg-Gd intermediate alloy is MgGd25 or MgGd30, and the Mg-Mn intermediate alloy is MgMn10, institute Stating Al-M intermediate alloy is one or more of AlTiB intermediate alloy, AlB intermediate alloy, AlTi intermediate alloy.More preferable institute Stating Al-M intermediate alloy is one or more of AlTi5B1, AlB3, AlB8, AlTi5, AlTi10.

Preferably, the refining agent of the concise use includes each component of following weight percent: 55%KCl, 25% CaCl₂, 5%CaF₂, 15%BaCl₂。

Preferably, the refining agent dosage of the concise addition is the 1.0~3.5% of raw material gross weight.

Preferably, the temperature of the refining is 720~730 DEG C, and the mixing time of refining treatment is 10~15min.

Preferably, the technological parameter of the second level solution treatment are as follows: the first order, 480~490 DEG C of temperature, time 36h~ 48h；The second level, 535~545 DEG C of temperature, time 1h~2h.

Preferably, the second level solution treatment suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting include the following steps: by Casting alloy is put into solid solution furnace, is warming up to 200-250 DEG C with 5-8 DEG C/min, is passed through protective gas, is continued with 5-8 DEG C/min 480~490 DEG C of first order solid solubility temperature are warming up to, starts timing when reaching solid solubility temperature, 36h~48h is kept the temperature, then with 6- 10 DEG C/h is warming up at a slow speed second level solution treatment, and temperature is maintained at 535~545 DEG C, keeps the temperature 1h~2h, then that sample is quick It is transferred on quenching unit and carries out water hardening.

Preferably, the technological parameter of the artificial aging processing are as follows: 185~215 DEG C of temperature, time 12h~36h.

Preferably, it is handled suitable for the artificial aging of the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, casting alloy is carried out Artificial aging processing, is maintained at 185~215 DEG C for furnace temperature, starts timing when reaching aging temp, keeps the temperature 12h~36h, out Room temperature is air-cooled to after furnace.

Preferably, the protective gas is argon gas；Or SF₆And CO₂Mixed gas, wherein SF₆Volume fraction be 0.2%.

The advantages of preparation method provided by the invention suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, has: (1) existing 720 DEG C are added the rare earth element Mg-Gd intermediate alloy of easy scaling loss, and keep the temperature fusing at low temperature, improve receiving for rare-earth Gd Rate；(2) refining treatment, which uses, is free of MgCl₂Dedicated refining agent, further reduced the scaling loss of rare-earth Gd in refining process. (3) heat treatment of high-toughness heat-resistant casting Mg-Gd alloy of the present invention includes two processes of solution treatment and ageing treatment. It is molten in magnesium matrix to sufficiently promote Gd and Zn by 480~490 DEG C of the first order temperature of second level solution treatment, time 36h~48h Xie Du eliminates the coarse precipitated phases such as LPSO；535~545 DEG C, time 1h~2h of the first order temperature of second level solution treatment, in short-term Between keep the temperature and further eliminate the coarse phase such as undissolved LPSO, existing regional segregation, microsegregation in casting are eliminated, so that closing The homogenization of composition of gold to improve the performance of alloy, and prevents heat treatment burn-off phenomenon.Furnace temperature is maintained at 185~ 215 DEG C, heat preservation 12h~36h carries out ageing treatment, and long period timeliness finally makes the transgranular precipitation Nano grade of alloy, disperse thin Small hardening constituent, so that alloy be made to have both excellent room temperature and high-temperature behavior.Heat treatment through the invention, alloying component are steady Fixed, crystal grain is not obviously grown up, and the performance of alloy is significantly improved, and method is simple, securely and reliably, easy to operate.

Compared with prior art, the present invention have it is following the utility model has the advantages that

High-toughness heat-resistant casting Mg-Gd alloy of the invention through low pressure casting, second level solution treatment and artificial aging heat at After reason, room temperature tensile intensity is 280MPa or more, and elongation percentage is 16% or more；Drawing by high temperature tensile strength is at 200 DEG C 190MPa or more, elongation percentage are 16% or more, and comprehensive performance reaches the performance of the cast aluminium alloy golds such as A380；Provided preparation side Method have many advantages, such as simple process, it is high-efficient, be suitble to large-scale production, meet aerospace, military project, automobile and other industries to light weight Change the high demand of development.

Detailed description of the invention

Upon reading the detailed description of non-limiting embodiments with reference to the following drawings, other feature of the invention, Objects and advantages will become more apparent upon:

Fig. 1 is that diecast magnesium alloy as-cast metallographic structure figure is prepared in embodiment 4.

Specific embodiment

The present invention is described in detail combined with specific embodiments below.Following embodiment will be helpful to the technology of this field Personnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that the ordinary skill of this field For personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made.These belong to the present invention Protection scope.

Embodiment 1

The weight percent for a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting that the present embodiment is related to are as follows: press Stoichiometric, 4.0%Gd, 1.2%Zn, 1.2%Al, 0.3%Mn, 0.05%Ti, 0.03%B, surplus is Mg and other can not The impurity avoided.

Preparation method is: (1) by above-mentioned Mg-Gd alloying component and stoichiometric ratio, the dosage of raw material needed for calculating；It will Technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot and MgGd30 and MgMn10 intermediate alloy remove removing oxide layer and dry preheating To 200 DEG C；By the ingredient and stoichiometric ratio of alloy, the dosage of raw material needed for calculating；(2) industry of crucible height 25% will be accounted for After pure magnesium ingot is fused into molten bath at 680 DEG C, it is passed through protective gas argon gas, remaining magnesium ingot is added；(3) it is all melted to magnesium ingot Afterwards, 700 DEG C are warming up to, by point 2 additions of industrial-purity zinc and MgGd30 and MgMn10 intermediate alloy, and keep temperature constant It 700 DEG C, is stirred until all melting, and keep the temperature 30 minutes；(4) 40 minutes before low pressure casting, 730 DEG C are warming up to, to institute It states technical pure aluminium ingot, AlTi5B1 intermediate alloy, AlB3 intermediate alloy and sequentially adds waiting all fusings, raw material weight 1% is added Refining agent refined, 730 DEG C of the temperature of refining, the mixing time 10min of refining treatment, refining agent component press quality percentage Than are as follows: 55%KCl, 25%CaCl₂, 5%CaF₂, 15%BaCl₂.Furnace temperature is risen to 750 DEG C of heat preservations standings to promote within 10 minutes to be mingled with Sedimentation, obtains magnesium alloy fused mass；(5) magnesium alloy fused mass is cooled to 720 DEG C, skims surface scum, preheat sand mold mould Temperature is 20 DEG C, and low pressure casting process is controlled and be classified pressurization by proportioning valve, comprising: rises liquid, fills type, pressurization, guarantor Pressure, release stage.Wherein, the pressure in described liter of liquid stage is uniformly increased to 0.02MPa, and pressing time controls in 5s；It is described to fill The pressure in type stage is uniformly increased to 0.08MPa, and molten metal is full of casting mold type chamber under stress；The pressure of the pressurization stages is equal Even to be increased to 0.1MPa, pressing time controls in 10s；The dwell time of the packing stage controls in 220s.It is obtained after release High-toughness heat-resistant casts Mg-Gd alloy low pressure casting.(6) second level solution treatment is successively carried out to low pressure casting, by casting alloy It is put into solid solution furnace, is warming up to 200 DEG C with 5 DEG C/min, be passed through protective gas, continue to be warming up to first order solid solution with 5 DEG C/min 480 DEG C of temperature, start timing when reaching solid solubility temperature, keeps the temperature 36h, be then warming up at a slow speed at the solid solution of the second level with 10 DEG C/h Reason, temperature are maintained at 535 DEG C, keep the temperature 1h, water hardening then will be carried out on sample fast transfer to quenching unit.(7) to solid Molten treated casting alloy carries out artificial aging processing, and furnace temperature is maintained at 185 DEG C, starts to count when reaching aging temp When, 12h is kept the temperature, is air-cooled to room temperature after coming out of the stove, obtains the high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 280MPa, elongation percentage 21% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 190MPa, elongation percentage 28%.

Embodiment 2

The weight percent for a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting that the present embodiment is related to are as follows: press Stoichiometric, 8.0%Gd, 4.8%Zn, 0.8%Al, 0.1%Mn, 0.08%Ti, surplus is Mg and other are inevitably miscellaneous Matter.

Preparation method is: (1) by above-mentioned Mg-Gd alloying component and stoichiometric ratio, the dosage of raw material needed for calculating；It will Technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot and MgGd30 and MgMn10 intermediate alloy remove removing oxide layer and dry preheating To 180 DEG C；By the ingredient and stoichiometric ratio of alloy, the dosage of raw material needed for calculating；(2) industry of crucible height 20% will be accounted for After pure magnesium ingot is fused into molten bath at 685 DEG C, it is passed through the SF containing 0.2% volume fraction₆And CO₂Mixed gas, remaining magnesium is added Ingot；(3) after magnesium ingot all fusing, 710 DEG C are warming up to, industrial-purity zinc and MgGd30 and MgMn10 intermediate alloy point 4 times are added Enter, and keep temperature constant at 710 DEG C, is stirred until all melting, and keep the temperature 40 minutes；(4) 60 points before low pressure casting Clock is warming up to 730 DEG C, to the technical pure aluminium ingot, AlTi10 intermediate alloy sequentially add waiting all fusing, be added raw material The refining agent of weight 3.5% is refined, 730 DEG C of the temperature of refining, the mixing time 10min of refining treatment, refining agent component By mass percentage are as follows: 55%KCl, 25%CaCl₂, 5%CaF₂, 15%BaCl₂.Furnace temperature is risen into 760 DEG C of heat preservations and stands 10 points Clock promotion is mingled with sedimentation, obtains magnesium alloy fused mass；(5) magnesium alloy fused mass is cooled to 720 DEG C, skims surface scum, in advance Hot sand mold mould temperature is 150 DEG C, and low pressure casting process is controlled and be classified pressurization by proportioning valve, comprising: rises liquid, fills Type, pressurization, pressure maintaining, release stage.Wherein, the pressure in described liter of liquid stage is uniformly increased to 0.05MPa, and pressing time control exists 8s；The pressure for filling the type stage is uniformly increased to 0.07MPa, and molten metal is full of casting mold type chamber under stress；The pressurization rank The pressure of section is uniformly increased to 0.15MPa, and pressing time controls in 15s；The dwell time of the packing stage controls in 300s. High-toughness heat-resistant casting Mg-Gd alloy low pressure casting is obtained after release.(6) second level solution treatment is successively carried out to low pressure casting, Casting alloy is put into solid solution furnace, is warming up to 250 DEG C with 8 DEG C/min, is passed through protective gas, continuation is warming up to 8 DEG C/min 490 DEG C of first order solid solubility temperature, start timing when reaching solid solubility temperature, keep the temperature 48h, is then warming up to the at a slow speed with 6 DEG C/h Second level solution treatment, temperature are maintained at 545 DEG C, keep the temperature 2h, then will carry out water cooling on sample fast transfer to quenching unit and quench Fire.(7) artificial aging processing is carried out to the casting alloy after solution treatment, furnace temperature is maintained at 215 DEG C, when arrival aging temp When start timing, keep the temperature 36h, be air-cooled to room temperature after coming out of the stove, obtain the high-toughness heat-resistant Mg-Gd conjunction for being suitable for low pressure casting Gold.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 309MPa, elongation percentage 16% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 218MPa, elongation percentage 16%.

Embodiment 3

The weight percent for a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting that the present embodiment is related to are as follows: press Stoichiometric, 7.0%Gd, 3.0%Zn, 0.5%Al, 0.2%Mn, 0.01%Ti, 0.01%B, surplus is Mg and other can not The impurity avoided.

Preparation method is: (1) by above-mentioned Mg-Gd alloying component and stoichiometric ratio, the dosage of raw material needed for calculating；It will Technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot and MgGd30 and MgMn10 intermediate alloy remove removing oxide layer and dry preheating To 200 DEG C；By the ingredient and stoichiometric ratio of alloy, the dosage of raw material needed for calculating；(2) industry of crucible height 20% will be accounted for After pure magnesium ingot is fused into molten bath at 675 DEG C, it is passed through protective gas argon gas, remaining magnesium ingot is added；(3) it is all melted to magnesium ingot Afterwards, 700 DEG C are warming up to, industrial-purity zinc and MgGd30 and MgMn10 intermediate alloy are added three times, and keep temperature constant It 700 DEG C, is stirred until all melting, and keep the temperature 30 minutes；(4) 40 minutes before low pressure casting, 730 DEG C are warming up to, to institute It states technical pure aluminium ingot, AlTi5 intermediate alloy, AlB3 intermediate alloy and sequentially adds waiting all fusings, raw material weight 2.5% is added Refining agent refined, 720 DEG C of the temperature of refining, the mixing time 15min of refining treatment, refining agent component press quality percentage Than are as follows: 55%KCl, 25%CaCl₂, 5%CaF₂, 15%BaCl₂.Furnace temperature is risen to 750 DEG C of heat preservations standings to promote within 10 minutes to be mingled with Sedimentation, obtains magnesium alloy fused mass；(5) magnesium alloy fused mass is cooled to 730 DEG C, skims surface scum, preheated metallic pattern Having temperature is 180 DEG C, and low pressure casting process controlled and be classified pressurization by proportioning valve, comprising: liter liquid, fill type, pressurization, Pressure maintaining, release stage.Wherein, the pressure in described liter of liquid stage is uniformly increased to 0.03MPa, and pressing time controls in 5s；It is described The pressure for filling the type stage is uniformly increased to 0.08MPa, and molten metal is full of casting mold type chamber under stress；The pressure of the pressurization stages It is uniformly increased to 0.15MPa, pressing time controls in 12s；The dwell time of the packing stage controls in 260s.After release Mg-Gd alloy low pressure casting is cast to high-toughness heat-resistant.(6) second level solution treatment is successively carried out to low pressure casting, casting is closed Gold is put into solid solution furnace, is warming up to 250 DEG C with 5 DEG C/min, is passed through protective gas, and continuation is warming up to the first order with 5 DEG C/min and consolidates 485 DEG C of solubility temperature, start timing when reaching solid solubility temperature, keep the temperature 42h, second level solid solution is then warming up at a slow speed with 10 DEG C/h Processing, temperature are maintained at 540 DEG C, keep the temperature 1.5h, water hardening then will be carried out on sample fast transfer to quenching unit.(7) Artificial aging processing is carried out to the casting alloy after solution treatment, furnace temperature is maintained at 200 DEG C, is started when reaching aging temp Timing, heat preservation for 24 hours, are air-cooled to room temperature after coming out of the stove, and obtain the high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 302MPa, elongation percentage 17% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 215MPa, elongation percentage 21%.

Embodiment 4

The weight percent for a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting that the present embodiment is related to are as follows: press Stoichiometric, 5.0%Gd, 2.5%Zn, 1.0%Al, 0.2%Mn, 0.08%B, surplus is Mg and other are inevitably miscellaneous Matter.

Preparation method is: (1) by above-mentioned Mg-Gd alloying component and stoichiometric ratio, the dosage of raw material needed for calculating；It will Technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot and MgGd30 and MgMn10 intermediate alloy remove removing oxide layer and dry preheating To 200 DEG C；By the ingredient and stoichiometric ratio of alloy, the dosage of raw material needed for calculating；(2) industry of crucible height 22% will be accounted for After pure magnesium ingot is fused into molten bath at 680 DEG C, it is passed through the SF containing 0.2% volume fraction₆And CO₂Hybrid protection gas, be added surplus Remaining magnesium ingot；(3) after magnesium ingot all fusing, 705 DEG C are warming up to, by industrial-purity zinc and MgGd30 and MgMn10 intermediate alloy point 4 Secondary addition, and keep temperature constant at 705 DEG C, it is stirred until all melting, and keep the temperature 30 minutes；(4) before low pressure casting 50 minutes, 730 DEG C are warming up to, waiting all fusings is sequentially added to the technical pure aluminium ingot, AlB8 intermediate alloy, raw material is added The refining agent of weight 3.0% is refined, 720 DEG C of the temperature of refining, the mixing time 15min of refining treatment, refining agent component By mass percentage are as follows: 55%KCl, 25%CaCl₂, 5%CaF₂, 15%BaCl₂.Furnace temperature is risen into 755 DEG C of heat preservations and stands 10 points Clock promotion is mingled with sedimentation, obtains magnesium alloy fused mass；(5) magnesium alloy fused mass is cooled to 740 DEG C, skims surface scum, in advance Thermometal type mold temperature is 250 DEG C, and low pressure casting process is controlled and be classified pressurization by proportioning valve, comprising: liter liquid, Fill type, pressurization, pressure maintaining, release stage.Wherein, the pressure in described liter of liquid stage is uniformly increased to 0.04MPa, pressing time control In 8s；The pressure for filling the type stage is uniformly increased to 0.07MPa, and molten metal is full of casting mold type chamber under stress；The pressurization The pressure in stage is uniformly increased to 0.1MPa, and pressing time controls in 10s；The dwell time control of the packing stage exists 220s.High-toughness heat-resistant casting Mg-Gd alloy low pressure casting is obtained after release.(6) second level solid solution is successively carried out to low pressure casting Processing, casting alloy is put into solid solution furnace, is warming up to 220 DEG C with 6 DEG C/min, is passed through protective gas, is continued with 6 DEG C/min liter Temperature starts timing when reaching solid solubility temperature to 480 DEG C of first order solid solubility temperature, keeps the temperature 48h, is then heated up at a slow speed with 8 DEG C/h To second level solution treatment, temperature is maintained at 535 DEG C, keeps the temperature 2h, water then will be carried out on sample fast transfer to quenching unit Cold quenching.(7) artificial aging processing is carried out to the casting alloy after solution treatment, furnace temperature is maintained at 185 DEG C, when arrival timeliness Start timing when temperature, keep the temperature 36h, be air-cooled to room temperature after coming out of the stove, obtains the high-toughness heat-resistant Mg- suitable for low pressure casting Gd alloy.

It is as shown in Figure 1 that the present embodiment prepares diecast magnesium alloy as-cast metallographic structure figure.By high-toughness heat-resistant Mg-Gd obtained Alloy carries out a. room temperature tensile test respectively；B.200 DEG C, in 200 DEG C of progress high temperature tensile properties after heat exposure processing in 200 hours Test, wherein the strain rate of extension test is 10^-5s^-1Static stretch.The room temperature of high-toughness heat-resistant magnesium alloy in this example Tensile strength is 295MPa, elongation percentage 19%；Drawing by high temperature tensile strength is 208MPa, elongation percentage 19% at 200 DEG C.

Embodiment 5

The weight percent for a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting that the present embodiment is related to are as follows: press Stoichiometric, 6.0%Gd, 1.2%Zn, 0.6%Al, 0.3%Mn, 0.04%Ti, 0.02%B, surplus is Mg and other can not The impurity avoided.

Preparation method is: (1) by above-mentioned Mg-Gd alloying component and stoichiometric ratio, the dosage of raw material needed for calculating；It will Technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot and MgGd30 and MgMn10 intermediate alloy remove removing oxide layer and dry preheating To 200 DEG C；By the ingredient and stoichiometric ratio of alloy, the dosage of raw material needed for calculating；(2) industry of crucible height 25% will be accounted for After pure magnesium ingot is fused into molten bath at 680 DEG C, it is passed through protective gas argon gas, remaining magnesium ingot is added；(3) it is all melted to magnesium ingot Afterwards, 710 DEG C are warming up to, by point 4 additions of industrial-purity zinc and MgGd30 and MgMn10 intermediate alloy, and keep temperature constant It 710 DEG C, is stirred until all melting, and keep the temperature 30 minutes；(4) 50 minutes before low pressure casting, 730 DEG C are warming up to, to institute It states technical pure aluminium ingot, AlTi10 intermediate alloy, AlB8 intermediate alloy and sequentially adds waiting all fusings, raw material weight is added 2.0% refining agent is refined, 730 DEG C of the temperature of refining, the mixing time 10min of refining treatment, and refining agent component presses matter Measure percentage are as follows: 55%KCl, 25%CaCl₂, 5%CaF₂, 15%BaCl₂.Furnace temperature is risen into 760 DEG C of heat preservations and stands 10 minutes rush Into sedimentation is mingled with, magnesium alloy fused mass is obtained；(5) magnesium alloy fused mass is cooled to 720 DEG C, skims surface scum, preheat sand Type mold temperature is 100 DEG C, and low pressure casting process controlled and be classified pressurization by proportioning valve, comprising: liter liquid, fill type, Pressurization, pressure maintaining, release stage.Wherein, the pressure in described liter of liquid stage is uniformly increased to 0.05MPa, and pressing time controls in 5s； The pressure for filling the type stage is uniformly increased to 0.08MPa, and molten metal is full of casting mold type chamber under stress；The pressurization stages Pressure is uniformly increased to 0.1MPa, and pressing time controls in 15s；The dwell time of the packing stage controls in 300s.Release After obtain high-toughness heat-resistant casting Mg-Gd alloy low pressure casting.(6) second level solution treatment is successively carried out to low pressure casting, will cast It makes alloy to be put into solid solution furnace, is warming up to 200 DEG C with 5 DEG C/min, be passed through protective gas, continue to be warming up to first with 5 DEG C/min 490 DEG C of solid solubility temperature of grade starts timing when reaching solid solubility temperature, keeps the temperature 36h, is then warming up to the second level at a slow speed with 10 DEG C/h Solution treatment, temperature are maintained at 545 DEG C, keep the temperature 1h, water hardening then will be carried out on sample fast transfer to quenching unit. (7) artificial aging processing is carried out to the casting alloy after solution treatment, furnace temperature is maintained at 215 DEG C, when reaching aging temp Start timing, keep the temperature 12h, be air-cooled to room temperature after coming out of the stove, obtains the high-toughness heat-resistant Mg-Gd suitable for low pressure casting and close Gold.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant Mg-Gd alloy is 290MPa, elongation percentage 18% in this example；Drawing by high temperature at 200 DEG C Tensile strength is 202MPa, elongation percentage 24%.

Comparative example 1

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 0.25%Gd, 3.0%Zn, 0.5%Al, 0.2%Mn, 0.01%Ti, 0.01%B, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 3.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 142MPa, elongation percentage 3.5% in this example；Drawing by high temperature is anti-at 200 DEG C Tensile strength is 110MPa, elongation percentage 13%.

Comparative example 2

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 4.0%Gd, 1.2%Zn, 1.5%Al, 0.3%Mn, 0.05%Ti, 0.03%B, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 1.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 270MPa, elongation percentage 16% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 175MPa, elongation percentage 21%.

Comparative example 3

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 6.0%Gd, 0.8%Zn, 0.6%Al, 0.3%Mn, 0.04%Ti, 0.02%B, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 5.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 277MPa, elongation percentage 14% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 176MPa, elongation percentage 19%.

Comparative example 4

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 8.0%Gd, 5.2%Zn, 0.8%Al, 0.1%Mn, 0.08%Ti, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 2.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 241MPa, elongation percentage 8.3% in this example；Drawing by high temperature is anti-at 200 DEG C Tensile strength is 149MPa, elongation percentage 12%.

Comparative example 5

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 7.0%Gd, 3.0%Zn, 0.5%Al, 0.5%Zr, 0.2%Mn, 0.01%Ti, 0.01%B, surplus is Mg and other are inevitably miscellaneous Matter.

Preparation method is same as Example 3；Wherein in step (4), MgZr30 intermediate alloy technical pure aluminium ingot, AlTi5 intermediate alloy, AlB3 intermediate alloy are added in magnesium alloy fused mass after being added, and to whole fusings.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 282MPa, elongation percentage 13% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 185MPa, elongation percentage 17.5%.

Comparative example 6

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 6.0%Gd, 1.2%Zn, 0.3%Al, 0.3%Mn, 0.04%Ti, 0.02%B, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 5.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 275MPa, elongation percentage 13% in this example；Drawing by high temperature tension at 200 DEG C Intensity is 172MPa, elongation percentage 16.5%.

Comparative example 7

The weight percent for the high-toughness heat-resistant Mg-Gd alloy that this comparative example is related to are as follows: press stoichiometric, 3.5%Gd, 2.5%Zn, 1.0%Al, 0.2%Mn, 0.08%B, surplus are Mg and other inevitable impurity.

Preparation method is same as Example 4.

High-toughness heat-resistant Mg-Gd alloy obtained is subjected to a. room temperature tensile test respectively；B.200 DEG C, 200 hours heat is sudden and violent In 200 DEG C of progress high temperature tensile properties tests after dew processing, wherein the strain rate of extension test is 10^-5s^-1Static stretch. The room temperature tensile intensity of high-toughness heat-resistant magnesium alloy is 248MPa, elongation percentage 8.5% in this example；Drawing by high temperature is anti-at 200 DEG C Tensile strength is 135MPa, elongation percentage 12%.

Description is described in detail to specific embodiments of the present invention above.It is to be appreciated that the present invention not office It is limited to above-mentioned particular implementation, those skilled in the art can make various deformations or amendments within the scope of the claims, This is not affected the essence of the present invention.

Claims (10)

1. a kind of high-toughness heat-resistant Mg-Gd alloy suitable for low pressure casting, which is characterized in that the Mg-Gd alloy includes pressing matter Measure the following element of percentage meter: 4.0~8.0%Gd, 1.2~4.8%Zn, 0.5~1.2%Al, 0.1~0.3%Mn, 0.01 ~0.08%M, surplus are Mg and other inevitable impurity, wherein M is at least one of Ti and B element.

2. as described in claim 1 be suitable for low pressure casting high-toughness heat-resistant Mg-Gd alloy, which is characterized in that the Zn with The mass ratio of Gd is 0.2~0.6:1.

3. as described in claim 1 be suitable for low pressure casting high-toughness heat-resistant Mg-Gd alloy, which is characterized in that the Zn and The gross mass of Al and the mass ratio of Gd are 0.3~0.7:1.

4. being suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting as described in claim 1, which is characterized in that described to account for The percent by weight of Mg-Gd alloy gross weight, when the M is the composite component of Ti and B, the mass fraction of Ti is 0.01~ 0.05%, the mass fraction of B is 0.01~0.03%.

5. a kind of preparation of the high-toughness heat-resistant Mg-Gd alloy as described in any one of claims 1 to 4 suitable for low pressure casting Method, which is characterized in that the method includes including the following steps:

S1, technical pure magnesium ingot, industrial-purity zinc, technical pure aluminium ingot, Mg-Gd intermediate alloy and Mg-Mn intermediate alloy are removed into oxidation Layer and dry be preheated to 180-200 DEG C；By the ingredient and stoichiometric ratio of the Mg-Gd alloy, the dosage of raw material needed for calculating；

S2, by the technical pure magnesium ingot for accounting for crucible height 20-25% 675-685 DEG C, be passed through protective gas under conditions of melt；

S3, after the magnesium ingot all fusing, 700~710 DEG C are warming up to, by the pure zinc, Mg-Gd intermediate alloy and Mg-Mn 2~4 additions of intermediate alloy point, keep temperature constant at 700~710 DEG C, stirring is extremely melted, and keeps the temperature 30-40 minutes；

40~60 minutes before S4, low pressure casting, it is warming up to 730-740 DEG C, the aluminium ingot, Al-M intermediate alloy is added, is melted, essence Refining is warming up to 750~760 DEG C of heat preservations and stands 10~20 minutes, obtains magnesium alloy fused mass；

S5, the magnesium alloy fused mass is cooled to 720~740 DEG C, skims surface scum, preheating sand mold type molds temperature to 25~ 150 DEG C or metal type dies temperature are to 180~250 DEG C；In low pressure casting process, rise the pressure rise in liquid stage to 0.02~ 0.05MPa, pressing time control in 5~8s, fill the pressure rise in type stage to 0.07-0.08MPa, molten metal fills under stress Full casting mold type chamber, to 0.1-0.15MPa, pressing time is controlled in 10~15s, the guarantor of packing stage for the pressure rise of pressurization stages The control of pressure time obtains Mg-Gd casting alloy low pressure casting after 200~300s, release；

S6, second level solution treatment, artificial aging processing are successively carried out to the Mg-Gd casting alloy low pressure casting, described in acquisition High-toughness heat-resistant Mg-Gd alloy.

6. the preparation method suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, feature exist as claimed in claim 5 In the Mg-Gd intermediate alloy is MgGd25 or MgGd30, and the Mg-Mn intermediate alloy is MgMn10, is closed among the Al-M Gold is one or more of AlTi5B1, AlB3, AlB8, AlTi5, AlTi10.

7. the preparation method suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, feature exist as claimed in claim 5 In the refining agent of the concise use includes each component of following weight percent: 55%KCl, 25%CaCl₂, 5%CaF₂、 15%BaCl₂。

8. the preparation method suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, feature exist as claimed in claim 5 In the refining agent dosage of the concise addition is the 1.0~3.5% of raw material gross weight；The temperature of the refining is 720~730 DEG C, the mixing time of refining treatment is 10~15min.

9. the preparation method suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, feature exist as claimed in claim 5 In the technological parameter of the second level solution treatment are as follows: the first order, 480~490 DEG C of temperature, time 36h~48h；The second level, temperature 535~545 DEG C of degree, time 1h~2h.

10. the preparation method suitable for the high-toughness heat-resistant Mg-Gd alloy of low pressure casting, feature exist as claimed in claim 5 In the technological parameter of the artificial aging processing are as follows: 185~215 DEG C of temperature, time 12h~36h.