CN1114707C

CN1114707C - Process for preparing non-tree-crystal Al alloy

Info

Publication number: CN1114707C
Application number: CN 01105114
Authority: CN
Inventors: 许珞萍; 邵光杰; 戴宗琳; 朱明原; 史文
Original assignee: University of Shanghai for Science and Technology
Current assignee: Shanghai University; University of Shanghai for Science and Technology
Priority date: 2001-01-09
Filing date: 2001-01-09
Publication date: 2003-07-16
Anticipated expiration: 2021-01-09
Also published as: CN1363707A

Abstract

The present invention relates to a process for preparing non-tree-crystal aluminium alloy, particularly to a process for preparing non-tree-crystal aluminium alloy metal blanks, which comprises the steps that after conventional melt, deslagging, degassing and refining are carried out to aluminium alloy, 0.1 to 2.0 wt% of Al-Si alloy powder with the grain size of 50 to 300 nm is added to a mother liquid at the temperature between 650 and 720 DEG C for agitation to cause the Al-Si to be uniformly distributed in the mother liquid, and then the mother liquid is cooled to a room temperature to obtain non-tree-crystal aluminium alloy. The present invention has the advantages of simple technology, convenient operation and low cost, can refine crystal grains in aluminium alloy casting and can enhance the practicality and the reliability of rheocasting.

Description

A kind of preparation method of non-tree-crystal Al alloy

The present invention relates to a kind of preparation method of non-tree-crystal Al alloy, particularly the preparation method of non-tree-crystal Al alloy metal stock.

Non-tree-crystal metal forming (semi-solid-state shaping) is the metal fabrication methods that has merged casting and forging process characteristics, and this method has save energy, prolong die life, improve the quality of products and performance and be convenient to the advantage of mass automatic production.The prerequisite of non-tree-crystal metal forming is to produce the metal stock of non-tree-crystal tissue earlier, the tissue of this blank and the branch of routine casting gained are crystalline organize different, its primary phase has the advantages that particulate state is the non-tree-crystal shape, make it have good thixotropic property at solid-liquid two-phase region, under certain shearing action, its viscosity sharply descends, thereby can utilize manufacturing process such as common die casting, extruding, die forging, injection to realize Semi-Solid Metals Forming.The existing method for preparing the non-tree-crystal metal has two classes.The first is carried out strong agitation in the process of setting of liquid metal, make the dentrite network skeleton that is easy to the nascent solid phase that forms in the process of setting broken, and keep disperse, homogeneous granules shape tissue topography, obtain semi-solid-state metal.As: United States Patent (USP) 3902544 (1975) has proposed a kind of method that adopts mechanical stirring to prepare the non-tree-crystal metal; United States Patent (USP) 3995678 (1976) has also proposed the employing induction stirring and has claimed hydromagnetics method (MHD) to prepare the method for non-tree-crystal metal again.It two is that the ingot casting with common dentrite tissue is applied reactive force, makes it produce deformation, and makes primary phase change particulate state in heat treatment process subsequently, thereby obtain the non-tree-crystal metal.For example: United States Patent (USP) 4.415.374 (1983) has proposed strain inducing fusing activation method (Strain Induced MeltActivation SIMA) preparation non-tree-crystal metal.The deficiency of aforesaid method one is that mechanical stirring equipment is huge, and agitator contacts all the time with molten metal in metal solidification process, easily causes molten metal to pollute; Though induction stirring has overcome churned mechanically deficiency, power consumption is bigger, and equipment is also complicated.The deficiency of aforesaid method two is production cost costlinesses, only is fit to produce undersized blank.

The preparation method who the purpose of this invention is to provide a kind of non-tree-crystal Al alloy, it has the advantage that technology is simple, easy to operate, cost is low and be not subjected to the billet size restriction.

For achieving the above object, the present invention be achieved in that aluminium alloy through the fusing of routine, remove slag, after the degasification, refining, ratio adding grain fineness number in 0.1-2.0%wt in the mother liquor that is in temperature between 650-720 ℃ is the Al-Si powdered alloy of 50-300nm, the Al-Si powdered alloy, press Al powder 15-85%wt by Al powder and Si powder, the mixed of Si powder 85-15%wt after the conventional mechanical alloying form, stir again the Al-Si powdered alloy is evenly distributed in the mother liquor, can obtain non-tree-crystal Al alloy through naturally cooling to room temperature.

The best proportioning of above-mentioned Al-Si powdered alloy is: Al powder and Si powder are pressed Al powder 40-60%wt, the mixed of Si powder 60-40%wt.

The present invention is owing to only need to add the Al-Si powdered alloy in the aluminium alloy mother liquor, can obtain non-tree-crystal Al alloy easily, both overcome that huge, the easy pollution of mechanical stirring equipment, power consumption in original method are big, production cost is expensive and be subjected to the deficiency of billet size restriction, had again that technology is simple, easy to operate, molten metal is pollution-free, be not subjected to billet size restriction and the low advantage of cost.In addition, the present invention also has the effect of refinement primary phase and eutectic structure, both can prepare non-tree-crystal Al alloy, but the crystal grain in the conventional aluminium alloy casting process of refinement again, material property is further improved, and can combine with rheocasting, to improve the practicality and the reliability of rheocasting technology.

Provide embodiments of the invention and process flow sheet below, and be described further:

Fig. 1, be process flow sheet of the present invention;

Fig. 2, the ZL101A alloy organizing shape appearance figure that obtains for the present invention;

Fig. 3, common ZL101A alloy organizing shape appearance figure.

By shown in Figure 1, Al powder and Si powder, press Al powder 15-85%wt, the ratio weighing and burden of Si powder 85-15%wt, its best proportioning is: Al powder and Si powder are pressed Al powder 40-60%wt, Si powder 60-40%wt, carry out mechanical alloying then, with the grain fineness number of X-ray diffraction mensuration Al-Si powdered alloy, obtaining grain fineness number is the Al-Si powdered alloy of 50-300nm, i.e. the short deformed nucleus agent of homogeneity Al-Si.Common ZL101A alloy through conventional fusing, remove slag, after the degasification, refining treatment, ratio in 0.1-2.0%wt in the mother liquor that is in temperature between 650-720 ℃ adds the short deformed nucleus agent of above-mentioned homogeneity Al-Si, it is evenly distributed in the mother liquor, pour into a mould, naturally cool to room temperature then, can obtain the non-tree-crystal Al alloy material base.

Fig. 2 is the ZL101A alloy organizing shape appearance figure that adopts the technical process acquisition of Fig. 1, white portion is primary-Al phase in Fig. 2, present rosette and oval-shaped mixed style, black part is divided into eutectic Si tissue, be more tiny needle-like and sheet, promptly eutectic structure has also obtained refinement when forming semi-solid alloy, and material property is further improved.

Fig. 3 is common ZL101A alloy organizing shape appearance figure, and white portion is primary-Al phase in Fig. 3, presents the crystalline tissue of branch of tangible prosperity, and black part is divided into eutectic structure, is needle-like and sheet.

Claims

1, a kind of preparation method of non-tree-crystal Al alloy, comprise aluminium alloy through the fusing of routine, remove slag, after the degasification, refining, it is characterized in that: the ratio adding grain fineness number in 0.1-2.0%wt in the mother liquor that is in temperature between 650-720 ℃ is the Al-Si powdered alloy of 50-300nm, the Al-Si powdered alloy is pressed Al powder 15-85%wt by Al powder and Si powder, the mixed of Si powder 85-15%wt after the conventional mechanical alloying form, stir again Al-Si is evenly distributed in the mother liquor, through naturally cooling to room temperature.

2, according to the preparation method of the described a kind of non-tree-crystal Al alloy of claim 1, it is characterized in that: the Al-Si powdered alloy, press Al powder 40-60%wt by Al powder and Si powder, the mixed of Si powder 60-40%wt forms.