CN103225028A

CN103225028A - Al-Er-Zr-Si heat-resistant aluminum alloy and its heat treatment technology

Info

Publication number: CN103225028A
Application number: CN2013100849305A
Authority: CN
Inventors: 聂祚仁; 田舒; 文胜平; 高坤元; 黄晖
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2013-03-15
Filing date: 2013-03-15
Publication date: 2013-07-31

Abstract

The invention relates to an Al-Er-Zr-Si heat-resistant aluminum alloy and its heat treatment technology, and belongs to the technical field of alloys. 0.05-0.25wt% of Er, 0.2-0.3wt% of Zr, 0.01-0.2wt% of Si and other inevitable impurities are added to a pure aluminum matrix. The solid solution ageing heat treatment technology of the alloy comprises a step of solid solution at 630-650DEG C for 20-30h, a step of water quenching to room temperature, and a step of isothermal ageing at 350DEG C. The Al-Er-Zr-Si heat-resistant aluminum alloy has a very substantial ageing reinforcement effect because of the composite micro-alloying of Er, Zr and Si, has a higher ageing reinforcement speed and a higher peak value hardness than an Al-Er-Zr alloy, and has a good heat resistance.

Description

A kind of Al-Er-Zr-Si heat-resisting aluminium alloy and thermal treatment process thereof

Technical field

The present invention relates to a kind of aluminum alloy materials and thermal treatment process thereof of microalloying, belong to field of metal alloy technology.

Technical background

Heat-resisting aluminium alloy is meant enough oxidation-resistances are at high temperature arranged and under the long duration of action of temperature and load (dynamically and static), has characteristics such as the good and density of plasticity_resistant deformation (creep) and destructiveness and thermal conductivity is low.Be used widely in weapons, boats and ships, Aeronautics and Astronautics, automobile and other industries, as piston, cylinder sleeve, connecting rod, casing, the cylinder cap of Tank and Armoured Vehicle engine, missile case, empennage, aircraft engine cylinder, blade, aircraft skin etc.

The resistance toheat key that improves aluminium alloy is will make to separate out the thermostability precipitated phase (it is slow with alligatoring to grow up, and the part recurring structure changes) that forms a large amount of disperses and distribute in the alloy under higher temperature condition.In recent years, a large amount of both at home and abroad scholars are to the be used as a large amount of research of rare earth element in the resistance toheat of aluminium alloy.These researchs mainly concentrate on the influence to aluminium alloy of La, Ce, Y, Sc, Zr and mishmetal, wherein deep to rare earth Sc research, in aluminium alloys such as Al-Si system, Al-Zn-Mg system and Al-Mg system, add Sc and all obtained gratifying result of study.Yet, add the production cost that Sc has increased aluminium alloy greatly, make to contain the application of Sc aluminium alloy in industry and be restricted.Er is joined in the aluminium alloy, can generate and Al ₃The L1 that the Sc effect is identical ₂The Al of structure ₃The Er phase can improve the recrystallization temperature of aluminium alloy, more can effectively play actively effect such as refined crystalline strengthening and dispersion-strengthened, improves the comprehensive use properties of aluminium alloy.And the price comparison of Er is cheap, adds a spot of Er element and can not increase substantially production cost in aluminium alloy, can be widely used in the industrial production.

Yet the solid solubility of Er in aluminium alloy is limited in the process of setting of conventional ingot metallurgy, has limited the further raising of its effect.Other can generate L1 by compound interpolation ₂The alloying element of structure precipitated phase might improve separates out density, thereby further brings into play the effect of alloying.Except Sc, Zr a kind ofly can generate metastable L1 ₂The alloying element of structure precipitated phase is behind Zr and the Er combined microalloying, at Al ₃Might make precipitated phase keep stable L12 structure under the inducing of Er phase, and can hinder Al ₃Therefore growing up and alligatoring of Er phase can obtain good strengthening effect and thermostability, and for example the described a kind of Al-Er-Zr alloy of patent of invention ZL201010515843.7 has significant ageing strengthening effect.But the precipitation process of Zr itself is very slow; especially need several thousand hours ability fully to separate out under the situation that composition is lower, the interpolation of Si can promote separating out of Zr, so Er; Zr and Si are compounded with the effect that may give full play to separately, play better microalloying effect.The present invention under the situation based on above consideration, has designed the Al-Er-Zr-Si alloy just, seeks its suitable composition scope and corresponding thermal treatment process.

Summary of the invention

The objective of the invention is to method, seek Er, Zr, the rule of the collaborative performance of Si strengthening effect, thereby the performance of raising aluminium alloy by combined microalloying.

Al provided by the present invention ?Er ?Zr ?the Si heat-resisting aluminium alloy, it is characterized in that, added 0.05～0.25%(weight percent in the pure aluminum substrate) Er, 0.2～0.3%(weight percent) Zr, 0.01 Si～0.2%(weight percent), and other unavoidable impurities.

Added 0.15～0.25%(weight percent in the further preferred pure aluminum substrate) Er, 0.25～0.3%(weight percent) Zr, 0.05～0.15%(weight percent) Si.

The preparation method of this alloy adds AlEr and the realization of AlZr master alloy in the process of melting aluminium, or further add aluminum silicon alloy, and regulate the element of alloy, smelting temperature is 780 ± 10 ℃, be incubated 30 minutes after arriving smelting temperature, cast with swage then.

Ingot casting carries out solid-solution and aging heat treatment subsequently, and its technology may further comprise the steps: at first 630 ± 10 ℃ of solid solutions 20～30 hours, shrend subsequently is to room temperature, then at 350 ℃ of isothermal agings.The soaking time of preferred 350 ℃ of isothermal agings 10 minutes-1000 hours, more preferably 1-100 hour.

The present invention is owing to adopted Er, Si and Zr combined microalloying, have highly significant and ageing strengthening effect faster, as shown in Figure 1, Al-0.2Er-0.28Zr-0.1Si (S3 sample) and Al-0.2Er-0.28Zr-0.2Si(S4 sample) relative Al-Er-Zr(S1, S2) alloy has improved the speed and the peak hardness of ageing strengthening effect, and this alloy has good heat-resistant.

Description of drawings

Fig. 1: 350 ℃ of isothermal aging curves;

Fig. 2: (1h) in short-term resistance toheat curve of S4 alloy;

Fig. 3: the high temperature compressed intensity of S4 alloy solid solution attitude and aging state.

Embodiment

Example 1: adopt plumbago crucible melting and iron mould casting to prepare alloy cast ingot, raw materials used is fine aluminium and Al-6Er, Al-4Zr, and Al-20Si master alloy, smelting temperature are 780 ± 10 ℃.Be incubated 30 minutes after arriving smelting temperature, cast with swage then.The alloy that has prepared 5 kinds of different designs compositions, and tested its actual constituent by XRF, as shown in table 1 below.

Table 1 technic metal composition

Sample

Design composition (wt.%)

The actual composition of Er

The actual composition of Zr

The actual composition of Si

?	?	（wt.%）	（wt.%）	（wt.%）
					S1	Al-0.2Er-0.15Zr	0.18	0.20	0.01
S2	Al-0.2Er-0.28Zr	0.21	0.30	0.01
					S3	Al-0.2Er-0.28Zr-0.1Si	0.25	0.29	0.11
S4	Al-0.2Er-0.28Zr-0.2Si	0.19	0.28	0.15
					S5	Al-0.1Er-0.28Zr-0.2Si	0.05	0.30	0.20

Example 2: 640 ± 10 ℃ of solid solutions 20 hours, shrend was to room temperature, then at 350 ℃ of isothermal agings to the alloy in the example 1.Fig. 1 has provided the changes in hardness curve of isothermal aging, and the highest hardness value of S3 and S4 sample will be higher than the S2 sample as we can see from the figure, and its time that reaches peak value of hardness will be faster than S2 number.Though S2, S3, the Er of S4, Zr composition are more approaching, and S3 is relative with S4, and the S2 sample has added Si, and the Si of 0.01% among the S2 is the impurity in the fine aluminium.This explanation Er, Zr, the compound interpolation of Si can be quickened the precipitated phase forming process, to such an extent as to and can improve precipitated phase density and improve hardness of alloy.

Example 3: S4 alloy in the example 1 was handled 20 hours 635 ± 10 ℃ of homogenizing, and shrend is to room temperature, and 350 ℃ of isothermal agings 100 hours, adopting cold rolling mode rolling reduction afterwards was 70% then; Rolling back was 200～600 ℃ of annealing 1 hour, its changes in hardness as shown in Figure 2, as seen in 200～375 ℃ of temperature ranges, hardness of alloy does not almost obviously descend, the temperature alloy rigidity just has significant decline more than 375 ℃, this recrystallization temperature that shows alloy has good heat-resistant about 400 ℃.

Example 4: S4 alloy in the example 1 was handled 20 hours 635 ± 10 ℃ of homogenizing, shrend is to room temperature, then 350 ℃ of isothermal agings 100 hours, adopt high temperature compression test (adopting Gleeble3500 to wait the axial compression test of contracting) afterwards respectively, test temperature is 300 ℃, and strain rate strain rate scope is 10 ^-3-50s ^-1, sample rises to test temperature with the rate of heating of 5 ℃/s, is incubated 3 minutes, begins distortion then, and the compression overall strain is 0.6.Its solid solution attitude and the high temperature compressed intensity of aging state as shown in Figure 3, as seen at 300 ℃, under the same strain speed, S4 aging state alloy rheological stress is higher than S4 solid solution attitude alloy, promptly S4 aging state alloy high-temp intensity is higher than S4 solid solution attitude alloy.

Claims

1. Al-Er-Zr-Si heat-resisting aluminium alloy, it is characterized in that, added the 0.05-0.25%(weight percent in the pure aluminum substrate) Er, the 0.2-0.3%(weight percent) Zr, the 0.01-0.2%(weight percent) Si, and other unavoidable impurities.

2. a kind of Al-Er-Zr-Si heat-resisting aluminium alloy of claim 1 is characterized in that, has added 0.15～0.25%(weight percent in the pure aluminum substrate) Er, 0.25～0.3%(weight percent) Zr, 0.05～0.15%(weight percent) Si.

3. the method for preparing the described aluminium alloy of claim 1, it is characterized in that, adding AlEr and AlZr master alloy are realized in the process of melting aluminium, or further add aluminum silicon alloy, regulate the element of alloy, smelting temperature is 780 ± 10 ℃, arrives behind the smelting temperature insulation 30 minutes, then with the swage casting and carry out solid-solution and aging heat treatment.

4. claim 1 Al-Er-Zr-Si heat-resisting aluminium alloy solid-solution and aging heat treatment method is characterized in that: at first at 630 ± 10 ℃ of solid solution 20-30 hours, shrend subsequently is to room temperature, then at 350 ℃ of isothermal agings.

5. according to the method for claim 4, it is characterized in that the soaking time of 350 ℃ of isothermal agings 10 minutes-1000 hours.

6. according to the method for claim 4, it is characterized in that the soaking time 1-100 of 350 ℃ of isothermal agings hour.