CN102943226B

CN102943226B - Composite thermal treatment method for converting hard and brittle phase beta-Mg17Al12 into continuous precipitated phase in cast-mode AZ80 magnesium alloy

Info

Publication number: CN102943226B
Application number: CN201210451956.4A
Authority: CN
Inventors: 张菊梅
Original assignee: Xian University of Science and Technology
Current assignee: Xian University of Science and Technology
Priority date: 2012-11-12
Filing date: 2012-11-12
Publication date: 2015-03-25
Anticipated expiration: 2032-11-12
Also published as: CN102943226A

Abstract

The invention discloses a composite thermal treatment method for converting a hard and brittle phase beta-Mg17Al12 into a continuous precipitated phase (a diamond sheet shape) in a cast-mode AZ80 magnesium alloy. The composite thermal treatment method comprises the following steps of: at first, placing an AZ80 magnesium-aluminum alloy casting material with an aluminum content of 7-10% into a thermal treatment furnace in protective atmosphere, slowly heating the AZ80 magnesium-aluminum alloy casting material to 400-430 DEG C for high-temperature solution treatment, keeping the temperature for 10-25 hours, and slowly cooling to a room temperature with the furnace; secondly, heating the AZ80 magnesium-aluminum alloy which is subjected to the high-temperature solution treatment, to 400-430 DEG C, keeping the temperature for 5-10 hours, and repeatedly carrying out the solution treatment; and thirdly, heating the AZ80 magnesium-aluminum alloy to 180-220 DEG C and carrying out aging treatment for 12-20 hours to enable a beta-Mg17Al12 phase to be precipitated in a continuous precipitated manner (the diamond sheet shape) and to be distributed on an alpha-Mg matrix in a diffusion manner, namely obtaining the high-strength high-tenacity AZ80 magnesium alloy. Therefore, the anti-tension strength, the yield strength, the Bush rigidity and the elongation rate of the cast-mode AZ80 magnesium alloy can be improved simultaneously; the application field of the magnesium alloy can be expanded; and the composite thermal treatment method has stronger popularization and application values.

Description

Hard crisp phase β-Mg in as-cast AZ80 Magnesium alloy 17al 12change the combined type heat treatment process of continuous precipitated phase into

Technical field

The invention belongs to chemical production technical field, particularly relate to hard crisp phase β-Mg in a kind of as-cast AZ80 Magnesium alloy ₁₇al ₁₂change the combined type heat treatment process of continuous precipitated phase (diamond platy) into.

Background technology

As-cast AZ80 Magnesium alloy is owing to being distributed with netted hard crisp phase β-Mg at α-Mg crystal boundary ₁₇al ₁₂and making the reduction of its toughness, deformability decline, the elongation of as-cast AZ80 Magnesium alloy only has 3% ~ 4%, Fig. 1 to be the schematic diagram that prior art casts AZ80 Microstructure of Magnesium Alloy usually, white hard crisp phase β-Mg ₁₇al ₁₂in net distribution in crystal boundary, Fig. 2 is the schematic diagram of the casting AZ80 magnesium alloy stretching fracture vertical section tissue that prior art provides, in net distribution in the hard crisp β-Mg of crystal boundary ₁₇al ₁₂fracture origin is become when stretching.

Summary of the invention

For as-cast AZ80 Magnesium alloy in prior art owing to being distributed with netted hard crisp phase β-Mg at α-Mg crystal boundary ₁₇al ₁₂and make the particular problem that its toughness reduces, deformability declines, the object of the invention is to, hard crisp phase β-Mg in a kind of as-cast AZ80 Magnesium alloy is provided ₁₇al ₁₂change the combined type heat treatment process of continuous precipitated phase into.

In order to realize above-mentioned task, the present invention takes following technical solution:

Hard crisp phase β-Mg in a kind of as-cast AZ80 Magnesium alloy ₁₇al ₁₂change the combined type heat treatment process of continuous precipitated phase into, it is characterized in that, carry out according to the following steps:

1) by aluminium content be 7-10% AZ80 magnalium casting material put into the heat treatment furnace being in protective atmosphere, 400 DEG C-430 DEG C are heated to the speed of 10-15 DEG C/min, carry out solution treatment, and be incubated 10-25 hour at such a temperature, slowly cool to room temperature with heat treatment furnace;

2) then the AZ80 magnalium after higher temperature solid solution is heated to 400 DEG C-430 DEG C with the speed of 10-15 DEG C/min again, and insulation re-starts higher temperature solid solution in 5-10 hour at such a temperature, then air cooling is to room temperature;

3) and then with the speed of 10-15 DEG C/min be heated to 180 DEG C-220 DEG C, and carry out the ageing treatment of 12-20 hour at this temperature, air cooling, to room temperature, makes β-Mg ₁₇al ₁₂be distributed on α-Mg matrix to separate out mode diffusion-precipitation continuously, namely obtain the AZ80 magnesium alloy of high-strength and high ductility.

Hard crisp phase β-Mg in as-cast AZ80 Magnesium alloy of the present invention ₁₇al ₁₂change the combined type heat treatment process of continuous precipitated phase into, first make AZ80 magnesium alloy aluminium atom when the high temperature solid solution of 400 DEG C-430 DEG C all be solid-solution in α-Mg distribution-free in the β-Mg of crystal boundary ₁₇al ₁₂phase, in furnace cooling process slowly, aluminium, magnesium atom are separated out with lamellar form and are evenly distributed on α-Mg matrix, will provide the tissue morphology of homogenizing for follow-up solid solution, timeliness; Carry out the high temperature solid solution of 400 DEG C-430 DEG C again, air cooling, to room temperature, just obtains the saturated solid solution α-Mg of magnesium, the distribution of aluminium atom homogenizing; Again by the ageing treatment of 180 DEG C-220 DEG C, aluminium, magnesium atom are just to separate out mode (diamond platy) β-Mg continuously ₁₇al ₁₂phase disperse educt is distributed on α-Mg matrix, improve the tensile strength of as-cast AZ80 Magnesium alloy, yield strength, Bush's hardness, elongation, reach the object improving magnesium alloy obdurability, expand the Application Areas of magnesium alloy, there is stronger propagation and employment and be worth.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the casting AZ80 Microstructure of Magnesium Alloy that prior art provides;

Fig. 2 is the schematic diagram of the casting AZ80 magnesium alloy stretching fracture vertical section tissue that prior art provides;

Fig. 3 is hard crisp phase β-Mg in the as-cast AZ80 Magnesium alloy that provides of the embodiment of the present invention ₁₇al ₁₂change the realization flow figure of the combined type heat treatment process of continuous precipitated phase into.

Fig. 4 is the macrograph (β-Mg after the thermal treatment of AZ80 magnesium alloy composite ₁₇al ₁₂the sheet that assumes diamond in shape mutually Dispersed precipitate is on α-Mg matrix, and left figure is use 5000 times of Electronic Speculum, and right figure is use 10000 times of Electronic Speculum).

Below in conjunction with drawings and the specific embodiments, application principle of the present invention is further described.

Embodiment

It is below the embodiment that contriver provides; it should be noted that; specific embodiment described is below only in order to explain the present invention; the invention is not restricted to these embodiments; all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should belong to protection scope of the present invention.

Embodiment 1:

See Fig. 3, this gives hard crisp phase β-Mg in as-cast AZ80 Magnesium alloy ₁₇al ₁₂change the realization flow of the combined type heat treatment process of continuous precipitated phase into, specifically comprise the following steps:

By aluminium content be 7-10% AZ80 magnalium casting material put into the heat treatment furnace being in protective atmosphere, be heated to 420 DEG C with the speed of 10 DEG C/min and carry out higher temperature solid solution, and be at this temperature incubated 25 hours, slowly cool to room temperature with heat treatment furnace;

Then by the AZ80 magnalium through higher temperature solid solution, be heated to 420 DEG C with the speed of 10 DEG C/min, and insulation re-starts solution treatment in 10 hours at this temperature, air cooling is to room temperature;

And then be heated to 200 DEG C with the speed of 10 DEG C/min, and carry out the ageing treatment of 15 hours at this temperature, air cooling, to room temperature, makes β-Mg ₁₇al ₁₂be distributed on α-Mg matrix to separate out mode (diamond platy) diffusion-precipitation continuously, the AZ80 magnesium alloy of high-strength and high ductility can be obtained.

Embodiment 2:

By aluminium content be 7-10% AZ80 magnalium casting material put into the heat treatment furnace being in protective atmosphere, be heated to 400 DEG C with the speed of 15 DEG C/min and carry out higher temperature solid solution, and be at this temperature incubated 20 hours, slowly cool to room temperature with heat treatment furnace;

Then by the AZ80 magnalium through higher temperature solid solution, be heated to 400 DEG C with the speed of 15 DEG C/min, and insulation re-starts solution treatment in 5 hours at this temperature, air cooling is to room temperature;

And then be heated to 220 DEG C with the speed of 15 DEG C/min, and carry out the ageing treatment of 12 hours at this temperature, air cooling, to room temperature, makes β-Mg ₁₇al ₁₂be distributed on α-Mg matrix to separate out mode (diamond platy) diffusion-precipitation continuously, the AZ80 magnesium alloy of high-strength and high ductility can be obtained.

Embodiment 3:

By aluminium content be 7-10% AZ80 magnalium casting material put into the heat treatment furnace being in protective atmosphere, be heated to 430 DEG C with the speed of 12 DEG C/min and carry out higher temperature solid solution, and be at this temperature incubated 20 hours, slowly cool to room temperature with heat treatment furnace;

Then by the AZ80 magnalium through higher temperature solid solution, be heated to 430 DEG C with the speed of 12 DEG C/min, and insulation re-starts solution treatment in 8 hours at this temperature, air cooling is to room temperature;

And then be heated to 180 DEG C with the speed of 12 DEG C/min, and carry out the ageing treatment of 20 hours at this temperature, air cooling, to room temperature, makes β-Mg ₁₇al ₁₂be distributed on α-Mg matrix to separate out mode (diamond platy) diffusion-precipitation continuously, the AZ80 magnesium alloy of high-strength and high ductility can be obtained.

The know-why adopted in the above-described embodiments is, first makes AZ80 magnesium alloy aluminium atom when the high temperature solid solution of 400 DEG C-430 DEG C all be solid-solution in α-Mg distribution-free in the β-Mg of crystal boundary ₁₇al ₁₂phase, in furnace cooling process slowly, aluminium, magnesium atom are separated out with lamellar form and are evenly distributed on α-Mg matrix, will provide the tissue morphology of homogenizing for follow-up solid solution, timeliness; Carry out the high temperature solid solution of 400 DEG C-430 DEG C again, air cooling, to room temperature, just obtains the saturated solid solution α-Mg of magnesium, the distribution of aluminium atom homogenizing; Again by the ageing treatment of 180 DEG C-220 DEG C, aluminium, magnesium atom are just to separate out mode (diamond platy) β-Mg continuously ₁₇al ₁₂phase disperse educt is distributed on α-Mg matrix (see Fig. 4), to make the tensile strength of as-cast AZ80 Magnesium alloy, yield strength, Bush's hardness, elongation improve simultaneously, reaches the object improving alloy obdurability, expands the Application Areas of alloy.Significant to the problem solving as-cast AZ80 Magnesium alloy plasticity low.

Through applicant's test, adopt combined type heat treatment process of the present invention, the mechanical performance index of AZ80 magnesium alloy (as cast condition) is after treatment as shown in table 1.Compared with the AZ80 magnesium alloy materials of conventional cast gained, its tensile strength index σ _bcan improve 35%, yield strength index σ _0.2can improve 15%, plasticity index δ can improve 20%.

Table 1: the mechanical property of AZ80 magnesium alloy after combined type heat process

Sample	HB	σ _0.2/MPa	σ _b/MPa	δ/%
					As cast condition	62.5	113.7	162.1	4.96
After combined type heat process	84.6	128.6	232.7	6.14

Claims

1. hard crisp phase β-Mg in an as-cast AZ80 Magnesium alloy ₁₇al ₁₂change the combined type heat treatment process of continuous precipitated phase into, it is characterized in that, carry out according to the following steps:

1), by aluminium content be 7-10% AZ80 magnalium casting material put into the heat treatment furnace being in protective atmosphere, be heated to 400 DEG C with the speed of 15 DEG C/min and carry out higher temperature solid solution, and be incubated 20 hours at this temperature, slowly cool to room temperature with heat treatment furnace;

2), then by the AZ80 magnalium through higher temperature solid solution, be heated to 400 DEG C with the speed of 15 DEG C/min, and insulation re-starts solution treatment in 5 hours at this temperature, air cooling is to room temperature;

3) and then with the speed of 15 DEG C/min be heated to 220 DEG C, and carry out the ageing treatment of 12 hours at this temperature, air cooling, to room temperature, makes β-Mg ₁₇al ₁₂be distributed on α-Mg matrix to separate out mode diffusion-precipitation continuously, the AZ80 magnesium alloy of high-strength and high ductility can be obtained.