CN117187643A - Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof - Google Patents
Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof Download PDFInfo
- Publication number
- CN117187643A CN117187643A CN202311161419.0A CN202311161419A CN117187643A CN 117187643 A CN117187643 A CN 117187643A CN 202311161419 A CN202311161419 A CN 202311161419A CN 117187643 A CN117187643 A CN 117187643A
- Authority
- CN
- China
- Prior art keywords
- magnesium
- lithium alloy
- semi
- die
- solid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- GCICAPWZNUIIDV-UHFFFAOYSA-N lithium magnesium Chemical compound [Li].[Mg] GCICAPWZNUIIDV-UHFFFAOYSA-N 0.000 title claims abstract description 107
- 229910000733 Li alloy Inorganic materials 0.000 title claims abstract description 106
- 239000001989 lithium alloy Substances 0.000 title claims abstract description 106
- 239000007787 solid Substances 0.000 title claims abstract description 81
- 238000004512 die casting Methods 0.000 title claims abstract description 67
- 238000002360 preparation method Methods 0.000 title abstract description 18
- 239000000956 alloy Substances 0.000 claims abstract description 52
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 52
- 238000003756 stirring Methods 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 22
- 238000003723 Smelting Methods 0.000 claims abstract description 19
- 238000005266 casting Methods 0.000 claims abstract description 14
- 239000002002 slurry Substances 0.000 claims description 34
- 239000011777 magnesium Substances 0.000 claims description 21
- 229910052782 aluminium Inorganic materials 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 11
- 239000002184 metal Substances 0.000 claims description 11
- 238000007670 refining Methods 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 8
- 239000011888 foil Substances 0.000 claims description 8
- 238000002347 injection Methods 0.000 claims description 7
- 239000007924 injection Substances 0.000 claims description 7
- 239000000155 melt Substances 0.000 claims description 7
- 229910018503 SF6 Inorganic materials 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 6
- SFZCNBIFKDRMGX-UHFFFAOYSA-N sulfur hexafluoride Chemical compound FS(F)(F)(F)(F)F SFZCNBIFKDRMGX-UHFFFAOYSA-N 0.000 claims description 6
- 229960000909 sulfur hexafluoride Drugs 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 5
- 238000010118 rheocasting Methods 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 2
- 230000001681 protective effect Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 16
- 230000008569 process Effects 0.000 abstract description 10
- 239000000463 material Substances 0.000 abstract description 5
- 239000011159 matrix material Substances 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 27
- 239000012071 phase Substances 0.000 description 22
- 230000000694 effects Effects 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 7
- 238000010099 solid forming Methods 0.000 description 4
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 3
- 229910052688 Gadolinium Inorganic materials 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 239000003063 flame retardant Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 230000009974 thixotropic effect Effects 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000010128 melt processing Methods 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000004154 testing of material Methods 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Abstract
The invention discloses an ultralight high-strength semisolid rheologic die casting magnesium-lithium alloy and a preparation method thereof, and belongs to the technical field of semisolid forming of magnesium-lithium alloy materials. Aiming at the problem of low mechanical property of as-cast magnesium-lithium alloy, the invention prepares the ultra-light high-strength semi-solid rheo die casting magnesium-lithium alloy by designing alloy components and utilizing atmospheric smelting, electromagnetic stirring and rheo die casting. The ultra-light high-strength magnesium-lithium alloy semi-solid rheological die casting technology is a near net forming technology, can refine a matrix phase and a second phase, improves the tissue compactness and the surface quality of castings, and greatly improves the mechanical properties of products. The invention can obtain the ultra-light high-strength magnesium-lithium alloy product with the tensile strength not lower than 230MPa and the elongation not lower than 15 percent. The method has the advantages of simple technical process, short flow, strong practicability and good application prospect.
Description
Technical Field
The invention relates to a metal forming method, in particular to an ultralight high-strength semisolid rheologic die-casting magnesium-lithium alloy and a preparation method thereof, which are particularly suitable for the semisolid rheoforming process of the ultralight high-strength magnesium-lithium alloy, and belong to the technical field of semisolid forming of metal materials.
Background
The magnesium-lithium alloy has a plurality of excellent performances as one of the metal structural materials with the lowest density in the practical application at present, so that the magnesium-lithium alloy becomes an ideal choice of lightweight component products. It has high specific strength and specific rigidity, and simultaneously has good machinability, excellent electromagnetic shielding capability, and excellent low-temperature plasticity and impact resistance. Therefore, the method has wide application prospect in the fields of aerospace, weapon equipment, 3C electronics and the like. However, there is a gap between the practical application of magnesium-lithium alloys and their potential, where the lower absolute strength is one of the main factors limiting their further development and application.
Semi-solid forming processing techniques are techniques for forming a two-phase slurry of non-dendrite solid-liquid phase coexistence between the liquidus and solidus temperatures of an alloy. Compared with the traditional liquid forming technology, the semi-solid forming processing technology has a plurality of advantages, including lower forming temperature, longer die life, improved production conditions and environment, grain refinement, reduced air holes and loose shrinkage cavities, improved tissue compactness, improved casting quality and the like. Semi-solid forming techniques can be divided into two process routes, thixotropic forming and rheoforming. Compared with thixotropic forming, the rheological forming has the advantages of shorter flow, lower energy consumption, lower cost and the like. The semi-solid rheo-die casting technology is a method for quickly injecting semi-solid slurry into a die and quickly forming under the action of pressure. The semi-solid rheo-die casting technology has the advantages of semi-solid rheo-forming and die casting, is an advanced manufacturing technology with wide application prospect, has the advantages of high efficiency, high precision, high strength, high toughness and the like, is suitable for forming and processing various metal alloys, and has very wide application prospect.
The preparation of the magnesium-lithium alloy by adopting the semi-solid rheodie casting technology can realize the following advantages: firstly, the magnesium-lithium alloy prepared by the process has fine grain size, uniform structure and fewer internal defects, so that the strength, hardness and toughness of the material are obviously improved, and the mechanical property of the material is improved. Secondly, the semi-solid slurry is injection molded under a certain pressure, so that the precision size and the surface quality can be higher, and the semi-solid slurry has the characteristic of precision molding. However, a semi-solid state rheocasting forming method suitable for the ultra-light high-strength magnesium-lithium alloy is not yet seen.
Because the magnesium element and the lithium element have higher activity, the combustion risk exists in the semi-solid forming process; in addition, the semi-solid interval of the conventional magnesium-lithium alloy is smaller, and the semi-solid temperature is difficult to control accurately, so that the components of the magnesium-lithium alloy need to be designed and optimized, and the ultra-light high-strength magnesium-lithium alloy suitable for rheologic die casting is developed to meet the requirements of the aerospace, military industry and high-end civil fields on light materials.
Disclosure of Invention
Aiming at the problem of low mechanical property of as-cast magnesium-lithium alloy and the defect of the prior art method, the invention aims to provide an ultralight high-strength semi-solid rheologic die casting magnesium-lithium alloy composition design and a preparation method thereof. It should be noted that the design of the invention aims at magnesium-lithium base alloy, mg and Li are base alloy, and Li content is very high; the preparation and processing methods of the magnesium-lithium alloy are greatly different from those of the magnesium alloy. At present, no research is available on a magnesium-lithium alloy semi-solid die casting forming technology. According to the invention, by adding rare earth elements Gd and Y, the semi-solid temperature interval of the magnesium-lithium alloy is improved, and meanwhile, the heat stability and strength of the alloy can be improved; the addition of Ca element can improve the flame retardant property of the magnesium-lithium alloy and prevent the alloy from burning in the preparation process. And carrying out melt processing by an electromagnetic stirring technology to obtain high-quality magnesium-lithium alloy semi-solid slurry, and then transferring the semi-solid slurry into die casting equipment to enable the semi-solid slurry to be injection molded under pressure.
The aim of the invention is realized by the following technical scheme:
the invention relates to an ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy, which comprises the following components in percentage by mass: 6 to 14 percent of Li, 4 to 12 percent of Al, 3 to 9 percent of Zn, 0.5 to 3 percent of Gd, 0.5 to 3 percent of Y, 1 to 5 percent of Ca and the balance of Mg.
As one embodiment of the invention, the mass ratio of Al to Ca+Gd+Y in the magnesium-lithium alloy is controlled to be more than 1.2:1. Ca element is added into the magnesium-lithium alloy as a flame retardant element, the addition amount of the Ca element is 1-5%, and RE element is added as a strengthening element, so that the Mg-Zn-RE and Al-RE phases are generated, and the magnesium-lithium alloy has a stronger strengthening effect.
The invention relates to a preparation method of an ultralight high-strength semi-solid rheological die casting magnesium lithium alloy, which comprises the following steps:
(1) Smelting: proportioning according to the mass percentages of all components in the alloy, smelting the alloy by adopting an air furnace, introducing protective gas, wrapping Li and Ca by aluminum foil, adding Ca firstly, adding Li finally, and fully stirring to obtain molten metal;
(2) Preparing semi-solid slurry: controlling the temperature of the magnesium-lithium alloy melt to be the solidus temperature T of the alloy s Electromagnetic stirring is carried out at the temperature of 10-30 ℃ to prepare semi-solid slurry;
(3) Rheo die casting: injecting the semi-solid alloy melt into a die casting die, applying pressure to fully fill the die cavity with the alloy, and opening the die after pressure maintaining to obtain an ultra-light high-strength semi-solid rheologic die casting magnesium-lithium alloy casting;
as one embodiment of the invention, in the step (1), the atmosphere smelting step of the magnesium-lithium alloy is that the Mg block is heated in a resistance furnace to be completely melted and gradually heated to 710-750 ℃, and CO is introduced at 400-500 DEG C 2 And SF (sulfur hexafluoride) 6 After the temperature reaches 710-750 ℃, adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy in sequence, cooling to 680-720 ℃, adding Li wrapped by aluminum foil, and refining for 10-20 min to obtain a magnesium-lithium alloy melt;
as an embodiment of the present invention, in the step (2), the temperature of the magnesium-lithium alloy melt should be controlled between solidus and liquidus, i.e. 550-650 ℃;
as one embodiment of the invention, in the step (2), the magnesium-lithium alloy melt is subjected to electromagnetic stirring to prepare semi-solid slurry, wherein the electromagnetic stirring parameters are as follows: the stirring voltage is 250-380V, and the stirring frequency is 10-40 Hz. The stirring voltage and frequency are too low, the shearing action is weaker, the effect of refining the primary alpha-Mg phase cannot be achieved, the stirring voltage and frequency are too high, strong convection of the melt can be caused, oxide films on the surface of the melt are damaged, and agglomeration of primary phase particles can be caused, so that the final performance of the alloy can be influenced due to the fact that the stirring voltage and frequency are too low or too high.
As one embodiment of the present invention, the melt is transferred to an electromagnetic stirring device and is subjected to electromagnetic stirring by introducing a shielding gas.
As an embodiment of the present invention, in step (3), the semi-solid rheodie casting process is: injecting the semi-solid slurry with the temperature of 550-650 ℃ into a die casting die, wherein the die preheating temperature is 200-300 ℃, the injection specific pressure is 30-70 MPa, the die casting speed is 30-60m/s, and the pressure maintaining time is 10-40 s.
The invention prepares the ultra-light high-strength magnesium-lithium alloy by utilizing the atmosphere smelting, electromagnetic stirring and rheological die casting, solves the problem of low mechanical property of the magnesium-lithium alloy, and realizes the semi-solid rheological die casting forming of the ultra-light high-strength magnesium-lithium alloy. The process technology of the invention can replace the traditional casting process to produce various magnesium-lithium alloy products, realizes the near-net forming of the ultra-light high-strength magnesium-lithium alloy, and has wide application prospect.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention designs an ultra-light double-phase high-strength magnesium-lithium alloy suitable for semi-solid rheological die casting, which forms reinforced rare earth phases Mg-Zn-RE and Al-RE by adding RE element and has stronger second-phase reinforcing effect. In addition, the addition of RE element can form one layer of compact oxide film on the surface of the melt to protect the melt and prevent the oxidation of the melt. The alpha+beta double-phase structure has good plasticity while ensuring high strength. The addition of Ca element can improve the flame retardance of the alloy, and the generated Al 2 The Ca phase has an excellent modulus reinforcing effect. A is thatThe addition of the elements l and Zn has a stronger solid solution strengthening effect, and in addition, for magnesium-lithium alloy (more than 6%) with high Li content, a large amount of Mg-Li- (Al, zn) strengthening phases can be formed by the addition of the elements Al and Zn, and the mass ratio of Al to Ca+RE can be controlled in a synergistic manner to regulate and control the solid solution strengthening and the second phase strengthening. The addition of the Li element with the mass fraction of 6-14% ensures the ultra-light characteristic of the alloy, and the density of the alloy is less than 1.6g/cm 3 So that the alloy has ultrahigh specific strength.
2. For magnesium-lithium alloy melt with high Li content (more than 6%), the chemical property is very active, the oxidation combustion is very easy, the conventional semi-solid slurry preparation process cannot be applied at all, a large amount of oxidized inclusions exist, and a high-quality slurry structure cannot be prepared. According to the invention, the electromagnetic stirring technology is adopted to prepare the magnesium-lithium alloy semi-solid slurry, the electromagnetic stirring auxiliary semi-solid slurry preparation process is optimized according to the characteristics of the magnesium-lithium alloy, and the fused mass is given a stronger shearing action on the premise of not damaging the oxide film on the surface of the fused mass, so that the particle size of a primary alpha-Mg phase can be greatly reduced, and the high-quality magnesium-lithium alloy semi-solid slurry is prepared. And the technology is simple in operation, green, pollution-free and easy to industrialize and popularize.
3. The ultra-light high-strength magnesium-lithium alloy is formed by adopting the semi-solid rheological die casting technology, the primary phase and the secondary phase can be obviously refined, the tissue compactness and uniformity of castings are improved, the mechanical properties of the products are greatly improved, and the ultra-light high-strength magnesium-lithium alloy products with the tensile strength of not less than 230MPa and the elongation of not less than 15% can be obtained. In addition, the technology solves the problem of rheoforming of the magnesium-lithium alloy with high Li content (more than 6%) in the atmospheric environment, can realize the integrated net forming of the ultra-light magnesium-lithium alloy complex structural member, can greatly reduce the weight of the product, and realizes the light weight of the complex structural member. Said invention is simple in technological process, short in flow, strong in practicality and extensive in application range.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a metallographic microscope photograph of a magnesium-lithium alloy prepared in comparative example 3 using conventional atmospheric melting and metal die casting processes;
fig. 2 is a metallographic micrograph of an ultralight high-strength semi-solid rheocasting formed magnesium-lithium alloy of example 1.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
Example 1
An ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy mainly comprises the following components in percentage by mass: li9%, al 7%, zn 5%, ca 2%, gd 1%, Y1%, and the mass ratio of Al to Ca+RE is 1.75:1, the balance of Mg;
the preparation method of the ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy comprises three stages of preparing semi-solid slurry by atmospheric smelting and refining and electromagnetic stirring and semi-solid rheological die-casting, and comprises the following specific steps:
(1) Smelting: proportioning according to the mass percentage of each component in the alloy, smelting the alloy by adopting an air furnace, heating the Mg block in a resistance furnace until the Mg block is completely melted, gradually heating to 730 ℃, and introducing CO at 450 DEG C 2 And SF (sulfur hexafluoride) 6 When the temperature reaches 730 ℃, adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy in sequence, cooling to 700 ℃, adding Li wrapped by aluminum foil, and refining for 15min to obtain a magnesium-lithium alloy melt;
(2) Preparing semi-solid slurry: controlling the temperature of the magnesium-lithium alloy melt at 600 ℃, placing the magnesium-lithium alloy melt into electromagnetic stirring equipment for electromagnetic stirring, and setting electromagnetic stirring parameters: stirring voltage is 300V, stirring frequency is 20Hz, and semi-solid slurry is prepared;
(3) Rheo die casting: injecting the semi-solid slurry with the temperature of 600 ℃ into a die casting die, wherein the preheating temperature of the die is 250 ℃, the injection specific pressure is 50MPa, the die casting speed is 40m/s, the dwell time is 20s, and opening the die after dwell to obtain the ultra-light high-strength semi-solid rheologic die casting magnesium lithium alloy casting.
Example 2
An ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy mainly comprises the following components in percentage by mass: 14% of Li, 10% of Al, 7% of Zn, 3% of Ca, 2.5% of Gd and 2.5% of Y, wherein the mass ratio of Al to Ca+RE is 1.25:1, the balance of Mg;
the preparation method of the ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy comprises three stages of preparing semi-solid slurry by atmospheric smelting and refining and electromagnetic stirring and semi-solid rheological die-casting, and comprises the following specific steps:
(1) Smelting: proportioning according to the mass percentage of each component in the alloy, smelting the alloy by adopting an air furnace, heating the Mg block in a resistance furnace until the Mg block is completely melted, gradually heating to 710 ℃, and introducing CO at 400 DEG C 2 And SF (sulfur hexafluoride) 6 Adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy in turn when the temperature reaches 710 ℃, cooling to 680 ℃, adding Li wrapped by aluminum foil, and refining for 10min to obtain a magnesium-lithium alloy melt;
(2) Preparing semi-solid slurry: controlling the temperature of the magnesium-lithium alloy melt at 580 ℃, placing the magnesium-lithium alloy melt into electromagnetic stirring equipment for electromagnetic stirring, and setting electromagnetic stirring parameters: stirring voltage is 350V, stirring frequency is 10Hz, and semi-solid slurry is prepared;
(3) Rheo die casting: injecting the semi-solid slurry with the temperature of 580 ℃ into a die casting die, wherein the preheating temperature of the die is 200 ℃, the injection specific pressure is 60MPa, the die casting speed is 60m/s, the dwell time is 30s, and opening the die after dwell to obtain the ultra-light high-strength semi-solid rheologic die casting magnesium lithium alloy casting.
Example 3
An ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy mainly comprises the following components in percentage by mass: li6%, al 4%, zn 3%, ca 1%, gd 0.5%, Y0.5%, the mass ratio of Al to Ca+RE is 2:1, the balance of Mg;
the preparation method of the ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy comprises three stages of preparing semi-solid slurry by atmospheric smelting and refining and electromagnetic stirring and semi-solid rheological die-casting, and comprises the following specific steps:
(1) Smelting: proportioning according to the mass percentage of each component in the alloy, smelting the alloy by adopting an air furnace, heating Mg blocks in a resistance furnace until the Mg blocks are completely melted, gradually heating to 740 ℃, and introducing CO at 500 DEG C 2 And SF (sulfur hexafluoride) 6 After the temperature reaches 740 ℃, adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy in sequence, cooling to 720 ℃, adding Li wrapped by aluminum foil, and refining for 20min to obtain a magnesium-lithium alloy melt;
(2) Preparing semi-solid slurry: controlling the temperature of the magnesium-lithium alloy melt at 630 ℃, placing the magnesium-lithium alloy melt into electromagnetic stirring equipment for electromagnetic stirring, and setting electromagnetic stirring parameters: stirring voltage is 250V, stirring frequency is 40Hz, and semi-solid slurry is prepared;
(3) Rheo die casting: injecting the semi-solid slurry with the temperature of 630 ℃ into a die casting die, wherein the preheating temperature of the die is 300 ℃, the injection specific pressure is 30MPa, the die casting speed is 40m/s, the dwell time is 10s, and opening the die after dwell to obtain the ultra-light high-strength semi-solid rheologic die casting magnesium lithium alloy casting.
Comparative examples 1 to 4
The magnesium-lithium alloy described in comparative example 1 and the preparation method thereof are comparative examples of example 1, and the specific alloy components consist of the following components in percentage by mass: the balance of 9% Li, 7% Al, 5% Zn, 1% Gd, and 1% Y was Mg, and the composition did not contain Ca element as compared with example 1.
The magnesium-lithium alloy of comparative example 1 was prepared in the same manner as in example 1.
The magnesium-lithium alloy described in comparative example 2 and the preparation method thereof are comparative examples of example 1, and the specific alloy components consist of the following components in percentage by mass: 9% of Li, 7% of Al, 5% of Zn, 2% of Ca and the balance of Mg, and does not contain RE element as compared with example 1.
The magnesium-lithium alloy of comparative example 2 was prepared in the same manner as in example 1.
The magnesium-lithium alloy in comparative example 3 adopts the same composition ratio as that in example 1, and also comprises the following compositions in percentage by mass: li9%, al 7%, zn 5%, ca 2%, gd 1%, Y1%, and the mass ratio of Al to Ca+RE is 1.75:1, the balance being Mg.
The magnesium-lithium alloy in comparative example 3 is prepared by adopting the methods of atmospheric smelting and metal die casting, and comprises the following specific steps:
proportioning according to the mass percentage of each component in the alloy, smelting the alloy by adopting an air furnace, heating the Mg block in a resistance furnace until the Mg block is completely melted, gradually heating to 730 ℃, and introducing CO at 450 DEG C 2 And SF (sulfur hexafluoride) 6 And (3) after the temperature reaches 730 ℃, sequentially adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy, cooling to 700 ℃, adding Li wrapped by aluminum foil, refining for 15min to obtain a magnesium-lithium alloy melt, and pouring the alloy melt into a metal mold to obtain an ingot with qualified components.
The magnesium-lithium alloy and the preparation method thereof described in comparative example 4 are comparative examples of example 1, and the composition ratio of the magnesium-lithium alloy is the same as that of example 1. The difference from example 1 is that comparative example 4 adopts a different electromagnetic stirring process for preparing semi-solid slurry, stirring voltages of 200V and 400V, stirring frequencies of 5Hz and 50Hz are selected, respectively, and the other preparation methods are the same as example 1.
Fig. 1 is a metallographic microscope photograph of a magnesium-lithium alloy prepared by a conventional atmospheric melting and metal die casting process in comparative example 3, fig. 2 is a metallographic microscope photograph of an ultra-light high-strength semi-solid rheo die casting magnesium-lithium alloy in example 1, and it is known by comparison that an alpha phase of the magnesium-lithium alloy in comparative example 3 cast by the conventional atmospheric melting and metal die casting exhibits a typical long-strip phase structure, while an alpha phase of the magnesium-lithium alloy in example 1 formed by semi-solid rheo die casting is obviously spheroidized and mainly consists of spherical phases, and the dispersion distribution of the spherical alpha phases is very favorable for improving mechanical properties.
Performance testing
The alloys of examples 1-3, comparative examples 1-4 were tested for mechanical properties using a Zwick/Roell Z100 type material testing machine and for density using a drainage method. The number of effective tests for each sample was not less than 3, and the average was taken. The test results of the properties of the obtained samples are shown in Table 1.
Table 1 results of performance tests of examples and comparative examples.
| Density (g/cm) 3 ) | Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) | |
| Example 1 | 1.56 | 238 | 168 | 15.8 |
| Example 2 | 1.53 | 240 | 171 | 16.1 |
| Example 3 | 1.55 | 236 | 165 | 18.2 |
| Comparative example 1 | 1.54 | 195 | 127 | 3.1 |
| Comparative example 2 | 1.53 | 208 | 140 | 12.5 |
| Comparative example 3 | 1.56 | 203 | 133 | 10.5 |
| Comparative example 4 | 1.56 | 205-215 | 135-145 | 12-15 |
As can be seen from Table 1, the magnesium-lithium alloy product prepared in comparative example 1 is the same as that in example 1, and does not contain Ca element compared with example 1, but because the alloy in comparative example 1 lacks the flame retardant effect of Ca element, the alloy is extremely easy to oxidize and burn in the atmospheric smelting process, the impurities in the alloy are more, the purity is low, and the alloy is harmful to the mechanical properties of the alloy, so that the elongation rate of the product is only 3.1%, and the tensile strength is only 195MPa.
The magnesium-lithium alloy product prepared in comparative example 2 is the same as in example 1, contains no RE element compared with example 1, and has lower mechanical properties and tensile strength of only 208MPa due to the lack of the strengthening effect of the high-strength stable RE phase.
Comparative example 3 was produced by casting using the alloy composition of example 1, but the casting process was different from that of example 1, and casting using a metal mold; compared with metal die casting, the magnesium-lithium alloy prepared in the embodiment 1 is formed by semi-solid rheologic die casting, the alpha phase of the matrix is more round and smaller, the distribution is more dispersed uniformly, and the structure is more compact, so that the mechanical property of the magnesium-lithium alloy prepared in the embodiment 1 is improved by 35MPa compared with that of the magnesium-lithium alloy prepared in the comparative embodiment 1, the elongation is improved by 50%, and the performance is remarkably improved.
Comparative example 4 the alloy composition of example 1 was used, and different electromagnetic stirring processes were used to prepare semi-solid slurries, with stirring voltages of 200V and 400V, and stirring frequencies of 5Hz and 50Hz, respectively, which were either too low or too high, both affecting the refining effect of the primary alpha phase and affecting the final properties of the magnesium-lithium alloy.
The ultra-light high-strength semi-solid rheologic die-casting magnesium lithium alloy obtained in the embodiment 1-3 of the technology has excellent mechanical properties, tensile strength of more than 230MPa, elongation of more than 15 percent and excellent semi-solid die-casting formability.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the invention.
Claims (7)
1. The ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy is characterized by mainly comprising the following components in percentage by mass: 6-14% of Li, 4-12% of Al, 3-9% of Zn, 0.5-3% of Gd, 0.5-3% of Y, 1-5% of Ca and the balance of Mg;
the magnesium-lithium alloy is prepared by a method comprising the following steps:
(1) Smelting: proportioning according to the mass percentages of all components in the alloy, smelting the alloy by adopting an air furnace, introducing protective gas, wrapping Li and Ca by aluminum foil, adding Ca firstly, adding Li finally, and fully stirring to obtain molten metal;
(2) Preparing semi-solid slurry: controlling the temperature of the magnesium-lithium alloy melt to be the solidus temperature T of the alloy s Above mentionedElectromagnetic stirring is carried out at the temperature of 10-30 ℃ to prepare semi-solid slurry;
(3) Rheo die casting: and injecting the semi-solid alloy melt into a die casting die, applying pressure to fully fill the die cavity with the alloy, and opening the die after pressure maintaining to obtain the ultra-light high-strength semi-solid rheological die casting magnesium-lithium alloy casting.
2. The ultra-light high-strength semi-solid rheocasting magnesium-lithium alloy according to claim 1, wherein the mass ratio of Al to Ca+Gd+Y in the magnesium-lithium alloy is controlled to be more than 1.2:1.
3. The ultra-light high-strength semi-solid rheo die casting magnesium lithium alloy according to claim 1, wherein the step (1) is specifically: heating Mg block in a resistance furnace until it is completely melted and gradually heating to 710-750deg.C, introducing CO at 400-500deg.C 2 And SF (sulfur hexafluoride) 6 And (3) after the temperature reaches 710-750 ℃, sequentially adding Ca, al, zn, mg-Gd intermediate alloy and Mg-Y intermediate alloy, cooling to 680-720 ℃, adding Li wrapped by aluminum foil, and refining for 10-20 min to obtain a magnesium-lithium alloy melt.
4. The ultra-light high-strength semi-solid rheo-die casting magnesium-lithium alloy according to claim 1, wherein in the step (2), the temperature of the magnesium-lithium alloy melt is controlled between solidus and liquidus, namely 550-650 ℃.
5. The ultra-light high-strength semi-solid rheological die-casting magnesium-lithium alloy according to claim 1, wherein in the step (2), the magnesium-lithium alloy melt is subjected to electromagnetic stirring to prepare semi-solid slurry, and the electromagnetic stirring parameters are as follows: the stirring voltage is 250-380V, and the stirring frequency is 10-40 Hz.
6. The ultra-light high-strength semi-solid rheocasting magnesium-lithium alloy according to claim 5, wherein the melt is transferred to an electromagnetic stirring device and is subjected to electromagnetic stirring by introducing a shielding gas.
7. The ultra-light high-strength semi-solid rheological die-casting magnesium lithium alloy according to claim 1, wherein in the step (3), semi-solid slurry with the temperature of 550-650 ℃ is injected into a die-casting die, the die-casting die preheating temperature is 200-300 ℃, the injection specific pressure is 30-70 MPa, the die-casting speed is 30-60m/s, and the dwell time is 15-30 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311161419.0A CN117187643A (en) | 2023-09-08 | 2023-09-08 | Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311161419.0A CN117187643A (en) | 2023-09-08 | 2023-09-08 | Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117187643A true CN117187643A (en) | 2023-12-08 |
Family
ID=88991928
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311161419.0A Pending CN117187643A (en) | 2023-09-08 | 2023-09-08 | Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117187643A (en) |
-
2023
- 2023-09-08 CN CN202311161419.0A patent/CN117187643A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107164677B (en) | A kind of heat-resistant creep-resistant magnesium alloy and preparation method thereof | |
| Ye et al. | Beneficial effects of Sc/Zr addition on hypereutectic Al–Ce alloys: modification of primary phases and precipitation hardening | |
| CN101857934B (en) | Heat-resistant magnesium alloy and preparation method thereof | |
| CN101532105A (en) | Rare-earth magnesium alloy and preparation method thereof | |
| CN112593132B (en) | High-strength semi-solid two-phase die-casting magnesium-lithium alloy and preparation method thereof | |
| CN104532078A (en) | AHS aluminum alloy and aluminum alloy extruded rod thereof | |
| Chen et al. | Microstructure and high temperature mechanical properties of the Mg-Gd-Y (-Nd)-Zr alloy | |
| CN114231800B (en) | High-performance low-carbon aluminum alloy and preparation method thereof | |
| CN108746508A (en) | A kind of production technology of more alloy cylinder caps | |
| CN105525117A (en) | Aluminum alloy material capable of being used for manufacturing cylinder cover and preparation method for aluminum alloy material | |
| Liao et al. | Microstructure evolution and enhanced fatigue behavior in the Mg-10Li-5Zn-0.5 Er alloys micro-alloyed with Yb | |
| CN107893181B (en) | Magnesium alloy ingot | |
| CN111041291B (en) | High-strength aluminum alloy material and preparation method thereof | |
| CN104862544A (en) | Aluminum alloy material capable of improving impact resistance for cylinder cover and manufacturing method of aluminum alloy material | |
| CN105063436A (en) | Silicon and aluminum alloy material used for novel cylinder cover and preparation method of silicon and aluminum alloy material | |
| CN101880806B (en) | Heatproof magnesium alloy and preparation method thereof | |
| CN117187643A (en) | Ultralight high-strength semi-solid rheological die-casting magnesium lithium alloy and preparation method thereof | |
| CN108866460B (en) | Aging process of Al-Si-Mg-Zr-Ti-Sc alloy | |
| CN109182865B (en) | High-strength rare earth-magnesium alloy material and preparation method thereof | |
| CN114457256B (en) | Stress relaxation resistant high-strength high-elasticity copper alloy and preparation method thereof | |
| CN116676517A (en) | High-strength semi-solid rheological extrusion casting magnesium-lithium alloy and preparation method thereof | |
| CN113789453B (en) | Method for improving high-temperature strength of heat-resistant aluminum alloy through Mn microalloying | |
| CN114686735A (en) | Wrought aluminum alloy with gradient structure and preparation method thereof | |
| CN104928548B (en) | It is a kind of suitable for high-strength heat-resistant magnesium alloy of sand casting and preparation method thereof | |
| CN105063391A (en) | High-silicon-content aluminum alloy material for cylinder cover and preparation method of high-silicon-content aluminum alloy material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |