A kind of hypoeutectic Al-Mg2The rotten and thinning method of Si alloys
Technical field
The invention belongs to aluminium alloy castings and melting technique field, more particularly to a kind of hypoeutectic Al-Mg2The change of Si alloys
Matter and thinning method.
Background technology
In traditional Al-Si-Mg alloys, Mg2Si is by solid gas coupling is heat-treated disperse educt as the second phase
Reinforced Al-matrix body.In recent years, Mg is directly precipitated from molten aluminum2Si phases and the Al-Mg formed2Si alloys, this is in hypereutectic composition
Also referred to as in-situ authigenic Mg2The composite material of Si/Al, by the extensive concern of domestic and foreign scholars.This material with it is traditional
Al-Si-Mg alloys are compared, amount containing Mg and Mg2Si phase volume fraction highers have higher specific stiffness, specific strength and wearability
Equal excellent performances, the Novel lightweight material as fields such as space flight and aviation and automobiles have wider application prospect.However,
The Mg being precipitated under as cast condition2Si compares coarse, nascent Mg2Si is in dendritic crystalline coarse, with holes, and eutectic Mg2Si is in then coarse
Chinese character shape, netted, rodlike and sheet, seriously isolate Al matrixes, lead to stress concentration, form formation of crack, deteriorate the power of alloy
Learn performance.In addition, for the Al-Mg of hypoeutectic ingredient2Si alloys are organized by primary α-Al and Mg2Si+ α-Al eutectic phase groups
At wherein pattern of the primary α-Al under as cast condition is that coarse branch is crystalline, is macroscopically column crystal, leads to alloy mechanical property
With the decline of the casting characters such as feeding, crack resistance.
In recent years, people using various processes for example mechanical alloying, hot extrusion, rolling, heat treatment, quickly solidification and
Metamorphism treatment etc. controls Mg2The size and pattern of Si phases.In these methods, Metamorphism treatment has easy to operate, at low cost, change
The advantages that matter significant effect, is increased by the way that P, La, Nd, Y, Sr, Na, Ni, Zr and B iso-metamorphism agent element are added into alloy melt
Add Mg2The nucleation rate of Si phases or the growth pattern for changing crystal, and then can effectively refine Mg2Si phases improve the mechanics of alloy
Performance.
Up to now, people are to hypereutectic Al-Mg2Si alloys, that is, in-situ authigenic Mg2The Metamorphism treatment of Si/Al composite materials
Etc. processes carried out numerous studies, and to hypoeutectic Al-Mg2The research of Si alloys is rarely reported.With hypereutectic Al-Mg2Si
Alloy is compared, hypoeutectic Al-Mg2The plasticity and toughness of Si alloys are more preferable, have more excellent comprehensive mechanical property, it is contemplated that have
Wider application scenario.On condition that coarse Chinese character shape, netted and sheet eutectic Mg2Si phases are effectively refined.Together
When refine primary α-Al dendrite, so that alloy mechanical property and casting character is further improved.
At present for hypoeutectic Al-Mg2The research of Si alloys is rarely reported.The Li et al. people of University Of Tianjin is to hypoeutectic Al-
10Mg2Si alloys carry out 520 DEG C × 6h solid solutions and the ageing treatment of 200 DEG C subsequent × 6h, being total in alloy after discovery processing
Brilliant Mg2Si phases by it is long it is rodlike be changed into short threadiness and spherical, tensile strength is increased to 234.6 MPa by 186 MPa,
See Journal of Alloys and Compounds, 2016,663 (5):15-19.Their research is also shown that hypoeutectic
Al-10Mg2Corrosion resistance of the Si alloys in 3.5wt.% NaCl solutions is also improved, and sees Materials
Characterization, 2016, 122(12):142-147.Lee of material science research institute of South Korea et al. pairs
AlMg5Si2Mn diecasting alloys do cold-rolling treatment before Homogenization Treatments, make the coarse eutectic Mg of interconnection2Si phases are crushed
At tiny fragment, to make the mechanical property of alloy be effectively improved, Materials Science and are seen
Engineering A, 2017, 685(8):244-252.Although these methods being capable of refining eutectic Mg2Si improves alloy force
Learn, the performances such as corrosion-resistant, but there are processes more, complex process and it is of high cost the shortcomings of.Therefore, there is an urgent need to research and develop both
It is easy and economical, it is suitable for hypoeutectic Al-Mg2Alterant, fining agent and the rotten, thinning method of Si alloys.
Up to now there is not yet there is refinement hypoeutectic Al-Mg2The report of Si alloy primary α-Al dendrite.For casting
Al-Si alloys mainly refine primary α-Al dendrite by adding fining agent into alloy melt.Currently used fining agent has
The intermediate alloys such as Al-Ti, Al-B, Al-Ti-B, Al-Ti-C, Al-Zr and KBF4、K2TiF6, TiC and K2ZrF6Etc. single or multiple
Close salt.The Ti class fining agents such as Al-Ti, Al -5Ti -1B and Al-Ti-C are suitable for the aluminium silicon of fine aluminium and silicon content less than 1.5%
Alloy is not obvious the hypoeutectic cast aluminium-silicon alloy thinning effect of silicon content >=5%, this is because (Ti1-x Six )Al3
The generation of compound reduces the Al as raw core agent3Ti and TiB2Amount.Studies have shown that the B classes such as Al-3B, Al -3Ti -3B are thin
Agent has preferable thinning effect to the hypoeutectic cast aluminium-silicon alloy of silicon content > 4%, but B is easily reacted with alterant element Sr,
Generate SrB6, consume Sr and B.For Al-Mg2Si alloys, due to wherein contain higher Mg amounts, Refining Elements be more easy to Mg and
Alterant element etc. forms non-raw nuclear compound, weakens rotten and thinning effect or causes the generation of casting flaw.Iranian Teheran
Fakhraei of university et al. has found, excessive B is added in Al-20Mg alloys or Zr will produce stomata, leads to alloy tensile
Materials & Design, 2014,56 (4) are shown in the reduction of performance:557-564.
Invention content
It is of the existing technology the purpose of the present invention is overcoming the problems, such as, provide that a kind of rotten, thinning effect is good, fade resistance
Good, strong applicability, metal mold, sand mold be all suitable for, the hypoeutectic Al-Mg of simple production process2The rotten and refinement side of Si alloys
Method.
Technical solution of the invention is:
(1)By the %Mg of 4-12.5wt. containing mass percent2Hypoeutectic Al-the Mg of Si phases2Si alloying ingredients, the wherein addition of Mg
Amount is:The scaling loss amount of calculation amount+10 ~ 30%;
(2)By step(1)After pure Al, the aluminium silicon intermediate alloy prepared is cleaned and dried, it is put into the graphite crucible of resistance furnace, in electricity
It is heated in resistance stove, until completely melted, at 720 DEG C, by aluminium foil package, the pure Mg blocks stone for preheating 300 DEG C of 300 DEG C of preheating
In black bell jar indentation melt, until fusing, stands 5min;
(3)The carbon trichloride graphite bell jar indentation step for preheating 300 DEG C of melt quality 0.05 ~ 0.2% will be accounted for(2)It obtains
In melt, refining degasification is carried out, 1 ~ 5 min is stirred at a temperature of 670 DEG C ~ 780 DEG C, the dross of bath surface is removed, obtains essence
Melt after refining;
(4)To step(3)Bi particles are added in obtained melt under conditions of temperature is 670 DEG C ~ 730 DEG C, stand 1 ~ 3 min,
Obtain the melt that Bi contents are 0.1-0.6wt. % mass percents;
(5)To step(4)Obtained melt is added Al-10Zr intermediate alloys or is contained under conditions of temperature is 720 DEG C ~ 800 DEG C
Zr compounds stand 5 ~ 15min, and after its fusing, 2 ~ 5 min of stirring melt makes Zr be uniformly distributed, and obtains Zr contents and is
The melt of 0.05-0.2wt. % mass percents;
(6)By step(3)To step(5)Obtained melt carries out refining treatment, by melt at being 700 DEG C ~ 780 DEG C in temperature
It is poured into casting mold, becomes casting or strand.
Step(4)The Bi is added with form of pure metal.
Step(5)The Zr is added with intermediate alloy or compound form.
Step(6)The casting mold is the metal mold and other casting molds of 250 DEG C of sand mold or preheating.
The advantages of technical solution of the present invention, is mainly reflected in:
1, using Bi pure metal particles as alterant, can effectively go bad hypoeutectic Al-Mg2Mg in Si alloys2Si phases, in Asia
Eutectic Al-Mg2After adding suitable Bi in Si alloys, eutectic Mg is had significantly changed2The pattern and size of Si, Mg2Si phases are by thick
Big Chinese character shape, netted and sheet are changed into tiny graininess, threadiness, and primary α-Al phase volume fraction increases, and occur
Apparent stigma of degeneracy and effect, solubility of the Bi in Al is extremely low, when to reach eutectic anti-for the melt of hypoeutectic and eutectic composition
When should put, is easily adsorbing and assembling the eutectic Mg being formerly precipitated2The growth interface forward position of Si phases is constantly blocked in eutectic growth
Eutectic Mg2The original twin steps of Si, and a large amount of new re-entrant angle twins are constantly inspired, make eutectic Mg2Si Branching Ratios are unmetamorphosed to be wanted
It is much more frequent, moreover, twin density significantly increases so that eutectic Mg2Si growth characteristics are changed into respectively by original anisotropy
To the same sex, then, eutectic Mg2Si is limited from branch before rotten and the sharp fibre for becoming a large amount of frequently branches of pattern of thick sheet development
Tie up shape growth, final eutectic Mg2The pattern and size of Si have the change of matter;In addition, enrichments of the Bi in liquid-solid boundary forward position
Constitutional supercooling is caused, as a result so that the balance crystallization temperature of liquid is greatly lowered at the forward position of interface, thus reduces liquid phase reality
Degree of supercooling reduces the speed of growth of eutectic structure, to reach refining eutectic Mg2The purpose of Si.
2, using Al-Zr intermediate alloys or compound containing Zr to hypoeutectic Al-Mg2Primary α-Al Phase in Si alloys has
Significant refining effect, in hypoeutectic Al-Mg2After adding suitable Zr in Si alloys, Primary α-Al Phase is had significantly changed
Pattern and size make it be changed into tiny equiax crystal by coarse columnar dendrite, and Zr is combined with the Al in alloy melt, raw
At ZrAl3Phase.ZrAl3Mutually close with the lattice constant of Primary α-Al Phase, mismatch between the two is only 0.925%, according to different
Matter forming core is theoretical, and mismatch is smaller, and the interatomic binding force of the two is stronger, easier in its substrate forming core, therefore, ZrAl3It can
Using the heterogeneous forming core core as primary α-Al, to refine Primary α-Al Phase.
3, to different content Mg2Hypoeutectic Al-the Mg of Si2Si alloys all have excellent rotten, thinning effect, expand
The application range of such alloy.
4, Bi alterants and Zr fining agents all have long-term effect, go bad, thinning effect, insensitive to cooling velocity, are applicable in
In the various casting production process such as metal mold, sand mold, die casting, since Bi is in eutectic Mg2The absorption in Si phase growth interfaces forward position is simultaneously
Coherent condition influenced by cooling velocity it is smaller, therefore Bi be added melt in, be either cast in metal mold, or in sand mold
In, eutectic Mg2Si can be refined effectively, i.e. Bi is in hypoeutectic Al-Mg2To eutectic Mg in Si alloys2The rotten effect of Si phases
Fruit is influenced smaller by cooling velocity;In addition, since bismuth with oxygen is not susceptible to chemically react, therefore in melt long-term heat preservation, cast
In the process, it is unlikely to be burnt, it is ensured that melt mesometamorphism eutectic Mg2The residual quantity of the minimum Bi of Si so that the modification effect of Bi has
There is long-term effect.
5, Bi alterants and Zr fining agents also have many advantages, such as easily operated, of low cost and safety and environmental protection.
Description of the drawings
Fig. 1 is that 100 times of bottom dies do not refine, go bad %Mg containing 10wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy
Micro-organization chart;
Fig. 2 is that 500 times of bottom dies do not refine, go bad %Mg containing 10wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is micro-
Organization chart;
Fig. 3 is 100 times of bottom die 0.13%Zr refinements, the rotten %Mg containing 10wt. of 0.41%Bi2Hypoeutectic Al-the Mg of Si phases2Si
Microstructure of the alloy micro-organization chart;
Fig. 4 is 500 times of bottom die 0.13%Zr refinements, the rotten %Mg containing 10wt. of 0.41%Bi2Hypoeutectic Al-the Mg of Si phases2Si
Microstructure of the alloy micro-organization chart;
Fig. 5 is that 100 times of bottom dies do not refine, go bad %Mg containing 4wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is micro-
Organization chart;
Fig. 6 is that 500 times of bottom dies do not refine, go bad %Mg containing 4wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is micro-
Organization chart;
Fig. 7 is 100 times of bottom die 0.09%Zr refinements, the rotten %Mg containing 4wt. of 0.1%Bi2Hypoeutectic Al-the Mg of Si phases2Si is closed
Golden metallographic microstructure figure;
Fig. 8 is 500 times of bottom die 0.09%Zr refinements, the rotten %Mg containing 4wt. of 0.1%Bi2Hypoeutectic Al-the Mg of Si phases2Si is closed
Golden metallographic microstructure figure;
Fig. 9 is that 100 times of bottom dies do not refine, go bad %Mg containing 12.5wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is aobvious
Micro-assembly robot figure;
Figure 10 is that 500 times of bottom dies do not refine, go bad %Mg containing 12.5wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy
Micro-organization chart;
Figure 11 is 100 times of bottom die 0.2%Zr refinements, the rotten %Mg containing 12.5wt. of 0.36%Bi2The hypoeutectic Al-of Si phases
Mg2Si microstructure of the alloy micro-organization chart;
Figure 12 is 500 times of bottom die 0.2%Zr refinements, the rotten %Mg containing 12.5wt. of 0.36%Bi2The hypoeutectic Al-of Si phases
Mg2Si microstructure of the alloy micro-organization chart;
Figure 13 is that 100 times of lower sand molds do not refine, go bad %Mg containing 10wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is micro-
Organization chart;
Figure 14 is that 500 times of lower sand molds do not refine, go bad %Mg containing 10wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is micro-
Organization chart;
Figure 15 is 100 times of lower sand mold 0.17Zr refinements, the rotten %Mg containing 10wt. of 0.6%Bi2Hypoeutectic Al-the Mg of Si phases2Si is closed
Golden metallographic microstructure figure;
Figure 16 is 500 times of lower sand mold 0.17Zr refinements, the rotten %Mg containing 10wt. of 0.6%Bi2Hypoeutectic Al-the Mg of Si phases2Si is closed
Golden metallographic microstructure figure;
Figure 17 is the not rotten %Mg containing 13.5wt. of 500 times of bottom dies2Hypoeutectic Al-the Mg of Si phases2Micro- group of Si microstructure of the alloy
Knit figure;
Figure 18 is the rotten %Mg containing 13.5wt. of 500 times of bottom die 0.44%Bi2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy
Micro-organization chart;
Figure 19 is the rotten %Mg containing 10wt. of 500 times of bottom die 0.06%Bi2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is aobvious
Micro-assembly robot figure;
Figure 20 is the rotten %Mg containing 10wt. of 500 times of bottom die 0.87%Bi2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is aobvious
Micro-assembly robot figure;
Figure 21 is that 100 times of bottom die 0.02%Zr refine %Mg containing 10wt.2Hypoeutectic Al-the Mg of Si phases2Si microstructure of the alloy is aobvious
Micro-assembly robot figure;
Figure 22 is 500 times of bottom die 0.64%Zr refinements, the rotten %Mg containing 10wt. of 0.47% Bi2The hypoeutectic Al-of Si phases
Mg2Si microstructure of the alloy micro-organization chart;
Figure 23 is the load-deformation curve of alloy.
Specific implementation mode
The present invention is for hypoeutectic Al-Mg2Si alloys are applicable in, including be added various alloy elements, it is additional and
The case where interior raw reinforced phase, following implementation of the present invention be intended merely to it is detailed for example, but the invention is not limited in
Following implementation, the various modifications under every core of the invention technical conditions and replacement, all belong to the scope of the present invention it
It is interior.
Below to hypoeutectic Al-Mg of the present invention2Si alloying components, alterant, fining agent and melting and founder
Skill condition illustrates:
Alloying component:Al-Mg of the present invention2Mg in Si alloys2The ingredient of Si is limited to 4 ~ 12.5wt. %, Al-Mg2Si is eutectic
Point is 13.9% cocrystallizing type alloy, eutectic Mg in alloy2Si phases are hardening constituent, and quantity, pattern, size and distribution are to its power
It is very big to learn performance influence, works as Mg2When Si < 4wt. %, Mg2Si phasors are low, and alloy strength is too low;Work as Mg2Si=13.9wt. %(Altogether
Brilliant ingredient)With 12.5wt. % < Mg2Si < 13.9wt. %(Nearly eutectic composition)When, our experiments demonstrated that, although Bi can disappear
Except a small amount of block-like nascent Mg occurred under as cast condition2Si phases, but to eutectic Mg2The modification effect unobvious of Si phases are shown in Figure 17, figure
18;Mg2Si is within the scope of 4 ~ 12.5wt. %, with Mg2The increase of Si amounts, alloy strength, hardness increase, and plasticity, toughness reduce;
In practical application, Mg can be reasonably selected according to the requirement of workpiece mechanical property2The quantity of Si phases, so that it is determined that final alloy at
Point.
Alterant:Bi alterants are to Al-Mg2Mg in Si alloys2The modification effect of Si phases depends primarily on the content of Bi, melts
There is best modification effect, as Bi contents < 0.1% in melt, Mg when Bi contents are 0.1 ~ 0.6% in body2Although Si phase Chinese characters
Shape disappears, and threadiness occurs, but there are still numerous strips, sheets, show rotten deficiency, see Figure 19;As Bi in melt
When content > 0.6%, Mg2Most of Si phases are still not fibrous, but part strip, sheet occur, show denaturalization phenomenon, and see
Figure 20.
Fining agent:Zr fining agents are to Al-Mg2The thinning effect of Primary α-Al Phase depends primarily on containing for Zr in Si alloys
Amount, i.e., as the heterogeneous forming core core ZrAl of primary α-Al3Production quantity number, melt Zr contents be 0.05 ~ 0.2% when have
There is best thinning effect, as Zr contents < 0.05% in melt, the ZrAl that is formed in melt3Very little, Primary α-Al Phase forming core position
It sets less, α-Al are still dendrite, show the deficiency of refinement, see Figure 21;As Zr contents > 0.2% in melt, not but not increase
Strong thinning effect, excessive Zr easily form ZrBi two-spots compound or Al-Zr-Bi ternary compounds with alterant Bi instead, disappear
The Bi atoms in melt are consumed, rotten deficiency is caused, although forming some fibre shape Mg2Si phases, but most of is still strip, piece
Shape is shown in Figure 22.
Smelting technology:Al-Mg2Si series alloys amount containing Mg is higher, and the present invention is smelting technology under air, is protected without gas
Shield or melting under vacuum, but the scaling loss of Mg should be strictly controlled, measure is:300 DEG C of preheating Mg blocks, are used in combination aluminium foil to wrap up, with pre-
In the graphite bell jar indentation melt of 300 DEG C of heat, until fusing, is added Bi later, after stirring slightly, that is, it is added among Al-Zr and closes
Gold, it is therefore an objective to avoid MAG block under high temperature from being in direct contact with the oxygen in air, shorten the fusing of magnesium and the soaking time of melt, make
The scaling loss amount of magnesium is controlled 10 ~ 30%, i.e. fusible in addition molten aluminum because the fusing point of pure Bi is low, without standing, but in Al-10Zr
Between alloy relative melting points it is high, standing is needed after addition 5 ~ 15 minutes, and after its fusing, 2 ~ 5 min of stirring melt makes Zr uniformly divide
Cloth.
Embodiment 1:
1, hypoeutectic Al-Mg is prepared using Al-15Si intermediate alloys, pure Al and pure Mg2Si alloys, wherein Mg and Si press 10.wt
%Mg2The ratio of Si is added, and the additive amount of Mg is:The scaling loss amount of calculation amount+10%, surplus are pure Al;
2, it after pure Al, the aluminium silicon intermediate alloy prepared step 1 is cleaned and dried, is put into the graphite crucible of resistance furnace, in resistance
Pure Al and Al-15Si intermediate alloys are heated in stove, until completely melted, at 720 DEG C, by aluminium foil package, preheat 300 DEG C
In the pure Mg blocks graphite bell jar indentation melt for preheating 300 DEG C, until fusing, stands 5min;
3, the carbon trichloride for accounting for melt quality 0.1% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 2 obtains, into
Row refining degasification, stirs 3min at a temperature of 740 DEG C, removes the dross of bath surface, the melt after being refined;
4, simple metal Bi particles at a temperature of 710 DEG C into melt are added to the melt that step 3 obtains, stand 2 min, obtains Bi
Content is the melt of 0.41wt. % mass percents;
5, Al-10Zr intermediate alloys under conditions of temperature is 750 DEG C are added to the melt that step 4 obtains, stand 10min, waits for
After it is melted, 3 min of stirring melt makes Zr be uniformly distributed, and obtains the melt that Zr contents are 0.13wt. % mass percents;
6, the carbon trichloride for accounting for melt quality 0.05% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 5 obtains,
Refining degasification is carried out, is stirred at a temperature of 740 DEG C, after refining, skimming, the metal mold of 250 DEG C of preheating is poured at a temperature of 740 DEG C
In, become casting.
Specific modification effect is shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4, and the Primary α-Al Phase being not added in Bi, Zr alloy is coarse
Dendrite is shown in Fig. 1, Mg2Si phases are coarse Chinese character, lath-shaped, see Fig. 2;Add Primary α-Al Phase after Bi, Zr in alloy by
Coarse branch is crystalline to be changed into tiny equiaxed dendrite shape, sees Fig. 3, Mg2Si phases become threadiness and minimal amount of tiny item
Shape is shown in Fig. 4;Refinement, it is rotten before the wax-anti dispersant of alloy be respectively 214.37MPa and 2.01%, refinement, it is rotten after
279.44MPa and 7.02% is respectively increased, sees Figure 23.
Embodiment 2:
1, hypoeutectic Al-Mg is prepared using Al-15Si intermediate alloys, pure Al and pure Mg2Si alloys, wherein Mg and Si press 4.wt %
Mg2The ratio of Si is added, and the additive amount of Mg is:The scaling loss amount of calculation amount+20%, surplus are pure Al;
2, it after pure Al, the aluminium silicon intermediate alloy prepared step 1 is cleaned and dried, is put into the graphite crucible of resistance furnace, in resistance
Pure Al and Al-15Si intermediate alloys are heated in stove, until completely melted, at 720 DEG C, by aluminium foil package, preheat 300 DEG C
In the pure Mg blocks graphite bell jar indentation melt for preheating 300 DEG C, until fusing, stands 5min;
3, the carbon trichloride for accounting for melt quality 0.05% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 2 obtains,
Refining degasification is carried out, 1min is stirred at a temperature of 780 DEG C, removes the dross of bath surface, the melt after being refined;
4, simple metal Bi particles at a temperature of 730 DEG C into melt are added to the melt that step 3 obtains, stand 3 min, obtains Bi
Content is the melt of 0. 1wt. % mass percents;
5, Al-10Zr intermediate alloys under conditions of temperature is 800 DEG C are added to the melt that step 4 obtains, stand 5min, waits for it
After fusing, 2 min of stirring melt makes Zr be uniformly distributed, and obtains the melt that Zr contents are 0.09wt. % mass percents;
6, the carbon trichloride for accounting for melt quality 0.2% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 5 obtains, into
Row refining degasification, is stirred at a temperature of 780 DEG C, and after refining, skimming, the metal mold of 250 DEG C of preheating is poured at a temperature of 780 DEG C
In, become casting.
Specific modification effect is shown in Fig. 5, Fig. 6, Fig. 7 and Fig. 8, and the Primary α-Al Phase being not added in Bi, Zr alloy is coarse
Dendrite is shown in Fig. 5, Mg2Si phases are coarse Chinese character, lath-shaped, see Fig. 6;Add Primary α-Al Phase after Bi, Zr in alloy by
Coarse branch is crystalline to be changed into tiny equiaxed dendrite shape, sees Fig. 7, Mg2Si phases become threadiness and minimal amount of tiny item
Shape is shown in Fig. 8;Refinement, it is rotten before the wax-anti dispersant of alloy be respectively 214.37MPa and 2.01%, refinement, it is rotten after
255.67MPa and 9.25% is respectively increased, sees Figure 23.
Embodiment 3:
1, hypoeutectic Al-Mg is prepared using Al-15Si intermediate alloys, pure Al and pure Mg2Si alloys, wherein Mg and Si press 12.5wt
%Mg2The ratio of Si is added, and the additive amount of Mg is:The scaling loss amount of calculation amount+30%, surplus are pure Al;
2, it after pure Al, the aluminium silicon intermediate alloy prepared step 1 is cleaned and dried, is put into the graphite crucible of resistance furnace, in resistance
Pure Al and Al-15Si intermediate alloys are heated in stove, until completely melted, at 720 DEG C, by aluminium foil package, preheat 300 DEG C
In the pure Mg blocks graphite bell jar indentation melt for preheating 300 DEG C, until fusing, stands 5min;
3, the carbon trichloride for accounting for melt quality 0.2% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 2 obtains, into
Row refining degasification, stirs 5min at a temperature of 670 DEG C, removes the dross of bath surface, the melt after being refined;
4, simple metal Bi particles at a temperature of 730 DEG C into melt are added to the melt that step 3 obtains, stand 1 min, obtains Bi
Content is the melt of 0.36wt. % mass percents;
5, compound containing Zr under conditions of temperature is 720 DEG C is added to the melt that step 4 obtains, stands 15min, waits for its fusing
Afterwards, 5 min of stirring melt, makes Zr be uniformly distributed, and obtains the melt that Zr contents are 0.2wt. % mass percents;
6, the carbon trichloride for accounting for melt quality 0.1% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 5 obtains, into
Row refining degasification, is stirred at a temperature of 700 DEG C, and after refining, skimming, the metal mold of 250 DEG C of preheating is poured at a temperature of 700 DEG C
In, become casting.
Specific modification effect is shown in Fig. 9, Figure 10, Figure 11 and Figure 12, and the Primary α-Al Phase being not added in Bi, Zr alloy is coarse
Dendrite, see Fig. 9, Mg2Si phases are coarse Chinese character, lath-shaped, see Figure 10;Primary α-Al after addition Bi, Zr in alloy
Mutually it is changed into tiny equiaxed dendrite shape by coarse branch is crystalline, sees Figure 11, Mg2Si phases become fibrous and minimal amount of thin
Small strip, is shown in Figure 12;It refines, the wax-anti dispersant of rotten preceding alloy is respectively 221.61MPa and 1.82%, refinement, change
287.76MPa and 6.81% are respectively increased after matter, sees Figure 23.
Embodiment 4:
1, hypoeutectic Al-Mg is prepared using Al-15Si intermediate alloys, pure Al and pure Mg2Si alloys, wherein Mg and Si press 10.wt
%Mg2The ratio of Si is added, and the additive amount of Mg is:The scaling loss amount of calculation amount+15%, surplus are pure Al;
2, it after pure Al, the aluminium silicon intermediate alloy prepared step 1 is cleaned and dried, is put into the graphite crucible of resistance furnace, in resistance
Pure Al and Al-15Si intermediate alloys are heated in stove, until completely melted, at 720 DEG C, by aluminium foil package, preheat 300 DEG C
In the pure Mg blocks graphite bell jar indentation melt for preheating 300 DEG C, until fusing, stands 5min;
3, the carbon trichloride for accounting for melt quality 0.2% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 2 obtains, into
Row refining degasification, stirs 4min at a temperature of 750 DEG C, removes the dross of bath surface, the melt after being refined;
4, simple metal Bi particles at a temperature of 710 DEG C into melt are added to the melt that step 3 obtains, stand 3 min, obtains Bi
Content is the melt of 0.6wt. % mass percents;
5, compound containing Zr under conditions of temperature is 760 DEG C is added to the melt that step 4 obtains, stands 12min, waits for its fusing
Afterwards, 4 min of stirring melt, makes Zr be uniformly distributed, and obtains the melt that Zr contents are 0.05wt. % mass percents;
6, the carbon trichloride for accounting for melt quality 0.05% is preheated to 300 DEG C of graphite bell jar be pressed into the melt that step 5 obtains,
Refining degasification is carried out, is stirred at a temperature of 730 DEG C, after refining, skimming, is poured into sand mold at a temperature of 730 DEG C.
Specific modification effect is shown in Figure 13, Figure 14, Figure 15 and Figure 16, compared with metal mold, under the conditions of sand mold, be not added with Bi,
Primary α-Al Phase in Zr alloys is dendrite, and more coarse, sees Figure 13, Mg2Si phases are coarse lath-shaped, see Figure 14;
Primary α-Al Phase after addition Bi, Zr in alloy is changed into tiny equiaxed dendrite shape, sees Figure 15, Mg2Si phases become tiny
Strip is shown in Figure 16;Refinement, it is rotten before the wax-anti dispersant of alloy be respectively 175.96MPa and 1.23%, it is refinement, rotten
After 244.69MPa and 3.83% is respectively increased, see Figure 23.