A kind of high temperature aluminium alloys with WB and LiH powder treatment and preparation method thereof
Technical field
The present invention relates to a kind of aldural, also relate to its preparation method.
Background technology
The aluminium alloy that deep processing is used often needs at first to be cast as large-scale ingot blank, such as slab ingot, pole etc., again by means such as rolling, extruding, forgings, be processed into various finished products, these processes basically all will with the heat treatment phase combination, if to the finished product that can directly use, then also will be through operations such as over-segmentation, surface working, Passivation Treatment.These processing means need aluminum alloy materials itself to possess good deep processing performance, comprise castability, press working deformation performance, heat treatment reinforcement performance, corrosion resistance, antifatigue destructive characteristics, surface working and coating property etc.Wherein, founding performance is the basis of aluminium alloy deep processing performance.Large-scale ingot blank, especially the above above pole of slab ingot, slab and diameter 500mm of thickness 500mm, can be the representative base material of Large Efficient deep processing, and be prefabricated into large-scale ingot blank, also be the first technology critical point whether test aluminum alloy materials itself is fit to carry out deep processing.
Because the large one-tenth branch of density is deposited in the foundry goods bottom in alloying constituent or the compound, float on top on the little composition of density.For example add this refractory metal of Ti and Al for crystal grain thinning and form dystectic flaky compound Al
3Ti can early crystallize out from aluminium alloy, when growing up to the gravity segregation that just easily sinks to producing local rules when larger, can see at the foundry goods fracture compound of the white bright ash of surfacing when segregation is more serious, primary silicon thick in the hypereutectic Al-Si aluminium alloy also easily forms segregation owing to density is less.
In addition when this aluminium alloy before cast owing to stirring the inhomogeneous eutectic segregation that causes, concentrate the place in Eutectic Silicon in Al-Si Cast Alloys, the high fragility of hardness is large, the process tool wearing and tearing are greatly; The position that Eutectic Silicon in Al-Si Cast Alloys is few forms α (Al) sosoloid soft spots, and intensity is low, adds not only to glue cutter man-hour, worsens processing characteristics, can make the distortion of α (Al) sosoloid cause machined surface hickie to occur under the effect of cutting force.When magnesium content was less than 0.6% (massfraction) in ZL108 (ZAlSi12Cu2Mg1) aluminium alloy, hickie also easily appearred in finished surface.
There is again the segregation of Cu element in the Al-Si-Cu aluminium alloy to cause that thick Al appears in regional area
2The Cu phase also is net distribution along crystalline substance, even if adopt thermal treatment it can not be dissolved in α (Al) sosoloid fully and remain in intergranular, thereby so that this kind alloy fragility increase.
Simultaneously, when adopting this aluminium alloy to cast, the normal appearance mainly contains oxide inclusion, molding material and flux mixture etc. various being mingled with in the foundry goods that casting is finished.Wherein, be mingled with aluminum oxide the most general.Especially in containing the aluminium alloy of Mg, majority is mingled with and is aluminum oxide and magnesian mixture, so in the aluminium alloy smelting process, the content of oxide inclusion is one of important mark matter of reflection aluminium liquid metallurgical quality.
This shows: the forming property of present aluminum alloy materials during except the large-scale ingot blank of founding is relatively poor, large-scale ingot blank is not high in the hardening capacity of heat treatment process, tempering resistance is relatively poor and can not satisfy higher mechanical property requirements or some property (as heat-resisting, anti-corrosion) etc., is significant deficiency yet.These defectives make it form the technology breakpoint that is difficult to cross in the process of the strong materials of weight such as field of engineering technology instead of steel goods and structure.
Summary of the invention
In order to overcome the deficiencies in the prior art, the invention provides a kind of preparation method of the high temperature aluminium alloys with WB and LiH powder treatment, can overcome the deficiency of existing aluminium alloy capability, improve its obdurability, plasticity and hardening capacity, for efficient deep processing provides high-end base material.
A kind of high temperature aluminium alloys with WB and LiH powder treatment, it is characterized in that by percentage to the quality, comprise 0.5~1.2% Si, the Fe less than or equal to 0.5%, 0.2~0.6% Cu, 0.15~0.35% Mn or Cr, 0.45~0.9% Mg, the Zn less than or equal to 0.2%, Ti less than or equal to 0.15%, the W of 1.0-2.0%, 0.06~0.12% B and 0.04~0.08% Li, surplus is Al and inevitable impurity; The content of described single contaminant is no more than 0.05% of total mass per-cent, and content of impurities is no more than 0.1% of total mass per-cent.
A kind of preparation method of described high temperature aluminium alloys with WB and LiH powder treatment is characterized in that step is as follows:
Step 1: aluminium ingot is added in the smelting furnace heating make it to melt fully, then add Si, the Fe less than or equal to 0.5%, 0.2~0.6% Cu, 0.15~0.35% Mn or Cr, 0.45~0.9% Mg, the Zn less than or equal to 0.2% of total product mass percent 0.5~1.2% by prescription and less than or equal to 0.15% Ti, dissolve fully and melt; Described melting process is finished in enclosed environment;
Step 2: 700~1000 ℃ of lower insulations, obtain alloy melt;
Step 3: adopt mixed gas that aluminium alloy melt is carried out the degassing and purifying operation, and will account for the WB of total product mass percent 1.06~2.12% and 0.045~0.09% LiH powder and join in the aluminium alloy melt with above-mentioned gas in the fluidization mode and mix, tungsten boride and lithium hydride are evenly distributed in aluminium alloy melt, and continue ventilation until react complete; Described mixed gas is: nitrogen or rare gas element or nitrogen and rare gas element are mixed to get according to arbitrary proportion;
Step 4: temperature adjustment to 680 after reaction finishes~730 ℃ obtains the aluminium alloy melt that melting is finished.
Aluminium ingot in the step 1 is replaced with molten aluminum liquid.
A kind of with described method of casting with the high temperature aluminium alloys of WB and LiH powder treatment, it is characterized in that: the aluminium alloy melt metaideophone of claim 2 melting is entered in the mold of foundry goods, use metal mold, sand mold or mixed type casting mode, adopt gravitational casting, pressure die casting or counter-pressure casting technique, the aluminum alloy casting of Casting Aluminum Alloy Based, particularly casting large-scale, thin-walled or complex construction.
A kind of with described a kind of method of casting with the high temperature aluminium alloys of WB and LiH powder treatment, it is characterized in that: the aluminium alloy melt of claim 2 melting is toppled over along chute come out of the stove, to vertical water cooling casting machine system, the pole that the large-scale slab ingot that casting processing ingot blank, particularly cast thickness 500mm are above and diameter 500mm are above.
The preparation method of the high temperature aluminium alloys with WB and LiH powder treatment provided by the invention; in wrought aluminium alloy with the W of Powdered adding 1.0-2.0%; the Li element of the B of 1.0-2.0% and 0.8-1.5%; add in the aluminium alloy melt process with protective gas with the fluidization form; have the specific surface area more much bigger than general cake mass; can realize disperseing fast and fully contacting with melt, significantly shorten and disperseed and the uniform time.Adopt simultaneously aldural of the present invention in castingprocesses, can in alloy graining process, effectively increase heterogeneous forming core core, thereby reach the effect of grain refining, strengthen alloy strength; And the element that adds can promote to form interstitial atom and gap mutually, during high temperature in α (Al) sosoloid solubleness large, and very little when room temperature, thereby make alloy have higher heat-treatability matter, after the thermal treatment, its intensity and hardness all have significant improvement.
Make a concrete analysis of as follows:
Without before adding above-mentioned element, except the common solution that form various elements, also contain Compound Phase that more following intermetallics form in the melt at this alloy:
θ phase (CuAl
2), Mg
2Si phase, N phase (Al
7Cu
2Fe), α phase (Al
12Fe
3Si), S phase (Al
2CuMg);
These metallic compounds are when melt cooling, because the minimum free energy principle of system, can not stable existence in the crystal grain that forms, will be under the driving that lattice distortion can differ from move and concentrate to crystal boundary, simultaneously, because the saturation solubility of alloying element in aluminum substrate significantly reduces along with drop in temperature, so cooling along with melt, oversaturated melt is constantly separated out the intermetallic compound that is rich in alloying element, and these compounds are difficult for merging in the intergranular enrichment to each other, in microtexture, become thick intergranular compound group, alloy produces crisp hardening effect, worsens the alloy casting forming property, reduces its homogeneity, toughness, solidity to corrosion and through hardening performance.So, when alloy graining becomes the basic structure of supersaturated solid solution matrix+intergranular metallic compound, be commonly referred to pure as-cast structure, the alloy with this tissue must just can have mechanical property and other technical indicator of satisfying the demand after the thermal treatment through " solid solution+timeliness ".
Although, can improve through the thermal treatment of formulation optimization processing and raising alloy property, still still there are a lot of defectives in alloy itself: insufficient strength is high, can not cast large specification type ingot etc.
The present invention passes through alternative, developed the mode of the processing melt of transition element, by adding 1.06~2.12% WB and 0.045~0.09% LiH, the nitrogen that is filled with in fusion process in addition is conducive to aluminium synthetic AlN in 800~1000 ℃ nitrogen atmosphere.Because the AlN that N and Al reaction generates is atomic crystal, genus quasi-diamond nitride the highlyest is stabilized to 2200 ℃; Room temperature strength is high, and the rising of intensity temperature descend slower, hot strength and resistance to corrosion that can the Effective Raise alloy; Thermal conductivity is good, and thermal expansivity is little, can improve the body material thermal shock resistance.Therefore, work as N
2When being filled with the high temperature aluminium alloys melt, itself just had the activity of giving birth to reaction with the various metals golden hair.So the concentration of the temperature when suitably regulating the cleaning molten operation and protectiveness nitrogen can be regulated the content of AlN in the melt, this further provides method for the content of regulating transition metal in the melt.
As seen: because the means of using in the present invention the fluidization nitride to process, the multi-effect of strengthening matrix and crystal grain thinning is integrated, replace master alloy, make aluminium alloy manufacturing concern no longer be limited by the master alloy manufacturer, be conducive to create the Green line of " nearly moulding, short flow process, intensive ", energy-saving and cost-reducing, reduce comprehensive cost; Simultaneously, in heat treatment process, owing to having formed excellent material microstructure, the unrelieved stress of ingot blank is less, therefore can significantly improve thermal treatment usefulness, improve the hardening capacity of ingot blank, when comparing with similar alloy, can produce thicker blank (bar that the sheet material that thickness 500mm is above and diameter 500mm are above) with " casting+heat treatment mode ", (the plate of moderate thickness manufacturing technology of thickness 15~200mm) realizes " rolling to cast generation " at series specification.
Generally speaking, the invention has the beneficial effects as follows:
In molten aluminium, caused multiple grain refining element, particle, thickization that prevents matrix and strengthening phase had good result.In cooled aluminum substrate, caused stable high interstitial atom and gap mutually, become new efficient strengthening phase, the intensity of material and hardness are improved.
The present invention is further described below in conjunction with embodiment.
Embodiment
Embodiment 1:
A kind of high temperature aluminium alloys with WB and LiH powder treatment by percentage to the quality, comprises 0.5% Si, 0.5% Fe, 0.2% Cu, 0.15% Mn, 0.9% Mg, 0.2% Zn, 0.15% Ti, 1.0% W, 1.0% B, 0.8% Li, surplus is Al and inevitable impurity, the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.1% of total mass per-cent.
The present invention also provides the preparation method of described a kind of high temperature aluminium alloys with WB and LiH powder treatment, adds tungsten boride and lithium hydride in the Combined Processing mode, may further comprise the steps:
Step 1: the component according to described aldural is got the raw materials ready, and comprises the Si, 0.5% Fe, 0.2% Cu, 0.15 Mn, 0.9% Mg, 0.2% Zn, 0.15% the Ti that account for total product mass percent 0.5%;
Step 2: add aluminium ingot or molten aluminum liquid first in smelting furnace, heating makes it to melt fully, adds first getting the raw materials ready of step 1 by formula rate, makes it to dissolve fully and melt, and 700 ℃ of lower insulations, obtains alloy melt after the refining; Melting process is finished in enclosed environment;
Step 3: use the mixed gas alloy melt of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion to carry out the degassing and purifying operation, and continue ventilation until react complete; To account for the total product mass percent simultaneously, 1.0% WB and 0.8% LiH powder join in the alloy melt with above-mentioned gas in the fluidization mode; Stir, tungsten boride and lithium hydride are evenly distributed in alloy melt, and fully react with alloy melt; Leave standstill, temperature adjustment to 680 ℃, obtain the aluminium alloy melt that melting is finished.
Embodiment 2:
A kind of high temperature aluminium alloys with WB and LiH powder treatment by percentage to the quality, comprises 0.9% Si, 0.4% Fe, 0.4% Cu, 0.25% Cr, 0.45% Mg, 0.1% Zn, 0.1% Ti, 1.5% W, 1.5% B, 1.2% Li, surplus is Al and inevitable impurity, the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.1% of total mass per-cent.
The present invention also provides the preparation method of described aldural, adds tungsten boride and lithium hydride in the Combined Processing mode, may further comprise the steps:
Step 1: the component according to described aldural is got the raw materials ready, and comprises the Si that accounts for total product mass percent 0.9%, 0.4% Fe, 0.4% Cu, 0.25% Cr, 0.45% Mg, 0.1% Zn, 0.1% Ti;
Step 2: add aluminium ingot or molten aluminum liquid first in smelting furnace, heating makes it to melt fully, adds first getting the raw materials ready of step 1 by formula rate, makes it to dissolve fully and melt, and 880 ℃ of lower insulations, obtains alloy melt after the refining; Melting process is finished in enclosed environment;
Step 3: use the mixed gas alloy melt of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion to carry out the degassing and purifying operation, and continue ventilation until react complete; To account for the total product mass percent simultaneously, 1.5% WB and 1.2% LiH powder join in the alloy melt with above-mentioned gas in the fluidization mode; Stir, tungsten boride and lithium hydride are evenly distributed in alloy melt, and fully react with alloy melt; Leave standstill, temperature adjustment to 700 ℃, obtain the aluminium alloy melt that melting is finished.
Embodiment 3:
A kind of high temperature aluminium alloys with WB and LiH powder treatment by percentage to the quality, comprises 1.2% Si, 0.3% Fe, 0.6% Cu, 0.35% Mn or Cr, 0.45% Mg, 0.12% Zn, 0.12% Ti, 2.0% W, 2.0% B, 1.5% Li, surplus is Al and inevitable impurity, the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.1% of total mass per-cent.
The present invention also provides the preparation method of described aldural, adds tungsten boride and lithium hydride in the Combined Processing mode, may further comprise the steps:
Step 1: the component according to described aldural is got the raw materials ready, and comprises the Si that accounts for total product mass percent 1.2%, 0.3% Fe, 0.6% Cu, 0.35% Mn or Cr, 0.45% Mg, 0.12% Zn, 0.12% Ti;
Step 2: add aluminium ingot or molten aluminum liquid first in smelting furnace, heating makes it to melt fully, adds first getting the raw materials ready of step 1 by formula rate, makes it to dissolve fully and melt, and 1000 ℃ of lower insulations, obtains alloy melt after the refining; Melting process is finished in enclosed environment;
Step 3: use the mixed gas alloy melt of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion to carry out the degassing and purifying operation, and continue ventilation until react complete; To account for the total product mass percent simultaneously, 2.0% WB and 1.5% LiH powder join in the alloy melt with above-mentioned gas in the fluidization mode; Stir, tungsten boride and lithium hydride are evenly distributed in alloy melt, and fully react with alloy melt; Leave standstill, temperature adjustment to 730 ℃, obtain the aluminium alloy melt that melting is finished.
After the aldural liquid of employing the inventive method melting is come out of the stove, carry out respectively the Foundry Production of different goods along following two kinds of flow processs.
Flow process one: topple over along chute and to come out of the stove, to vertical water cooling casting machine system, the large-scale slab ingot that casting processing ingot blank, particularly cast thickness 500mm are above and the pole more than the diameter 500mm.
Flow process two: metaideophone enters in the mold of foundry goods, uses metal mold, sand mold or mixed type casting mode, adopts gravitational casting, pressure die casting or counter-pressure casting technique, the aluminum alloy casting of Casting Aluminum Alloy Based, particularly casting large-scale, thin-walled or complex construction.