CN103255319A

CN103255319A - Al-Yb-Zr heatproof aluminium alloy and its heat treatment technology

Info

Publication number: CN103255319A
Application number: CN2013100843173A
Authority: CN
Inventors: 聂祚仁; 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: 2013-08-21

Abstract

An Al-Yb-Zr heatproof aluminium alloy and its heat treatment technology belong to the technical field of alloy. 0.07-0.25 wt% of Yb, 0.15-0.3 wt% of Zr and other unavoidable impurities are added into an aluminium matrix. A solid solution and ageing heat treatment process of the alloy comprises the following steps: firstly carrying out solid solution at 620+/-10 DEG C for 20-30 h, carrying out water quenching to room temperature, and carrying out isochronic ageing every 25 DEG C within 150-575 DEG C for 3 h. By Yb/Zr composite microalloying, the alloy provided by the invention has a very prominent ageing strengthening effect. In comparison with an Al-Er alloy, ageing strengthening effect and heat stability of the alloy are raised; in comparison with an Al-Zr alloy, the ageing precipitation process is obviously accelerated; and the alloy has good heat stability.

Description

A kind of Al-Yb-Zr 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 through microalloying, belong to field of metal alloy technology.

Technical background

There are incompatibility in intensity of aluminum alloy and electric conductivity between improving, and improve intensity and must improve the content of alloying element or improve the machining deformation amount, and the raising of the raising of alloying element content and amount of finish all will make specific conductivity descend.Simultaneously, though the interpolation of Zr can improve the resistance toheat of alloy in the general refractory alloy lead, the ageing strengthening effect of the Al-Zr alloy that Zr content is lower is relatively poor, and effect that it improves intensity is also not obvious; The content that increases the Zr element can play certain precipitation strength effect, but the electric conductivity of alloy significantly descends.This means that intensity and stable on heating raising all will make the corresponding decline of specific conductivity.Therefore to obtain the aluminium alloy conductor material of high strength, high heat resistance energy, high conductivity triplicity, then must find a kind of new guiding alloying constituent and preparation method thereof, under the condition of adding very a spot of alloying element, just can separate out the strengthening phase that a large amount of even dispersion distribute and have thermostability.

In recent years, both at home and abroad a large amount of scholars have been used as a large amount of research to rare earth element in aluminium alloy.These research mainly concentrate on La, Ce, Y, Sc, Zr and mishmetal to aluminium alloy influence, 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.Yb is joined in the aluminium alloy, can generate and Al ₃The L1 that the Sc effect is identical ₂The Al of structure ₃The Yb 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 Yb is cheap, adds a spot of Yb element and can not increase substantially production cost in aluminium alloy, can be widely used in the industrial production.Yet the solid solubility of Yb 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, but the precipitation process of Zr itself is very slow, especially needs several thousand hours ability fully to separate out under the situation that composition is lower.Behind Zr and the Yb combined microalloying, at Al ₃Might make its precipitation process in advance under the inducing of Yb phase.So Yb, Zr is compounded with the effect that may give full play to separately, plays good alloying effect.The present invention under the situation based on above consideration, has designed the Al-Yb-Zr alloy just, seeks its suitable composition scope and corresponding thermal treatment process.

Summary of the invention

The objective of the invention is to the method by combined microalloying, seek the composition range of the collaborative performance of Yb and Zr strengthening effect, aluminium or alloy matrix aluminum are played strengthening effect, thereby improve the performance of aluminium alloy.

Al-Yb-Zr alloy provided by the present invention is characterized in that adding in the pure aluminum substrate 0.12～0.25%(weight percent) Yb, 0.15～0.3%(weight percent) Zr, and other unavoidable impurities.

The preparation method of this alloy adds AlYb and the AlZr master alloy is realized in the process of melting aluminium, 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, its technology may further comprise the steps: at first 620 ± 10 ℃ of solid solutions 20～30 hours, shrend subsequently is to room temperature, then 150 ℃～timeliness when waiting between (400～575) ℃, detailed process is for taking a sample behind 25 ℃ of insulations of 150 ℃ of every increases 3h, for example 150 ℃/3h gets first sample, 150 ℃/3h+175 ℃/3h gets second sample, and 150 ℃/3h+1755 ℃/3h+200/3h gets the 3rd sample, and the like up in (400～575) ℃ end, a certain temperature in these (400～575) ℃ can meet the requirements by product, as the highest hardness value.

The present invention is owing to adopted Yb and Zr combined microalloying, ageing strengthening effect with highly significant, as shown in Figure 1, the Al-Yb alloy has improved ageing strengthening effect and thermostability relatively, the process that relative Al-Zr alloy then makes timeliness separate out is obviously accelerated, and this alloy has thermostability preferably.

Description of drawings

Fig. 1: between 150～575 ℃ when 25 ℃ are waited 3 hours Time-activity-curves;

Fig. 2: the recrystallize curve of S4 alloy.

Embodiment

Example 1: adopt plumbago crucible melting and iron mould casting to prepare alloy cast ingot, raw materials used is fine aluminium and Al-3Yb and Al-4Zr master alloy, and smelting temperature is 780 ± 10 ℃.Be incubated 30 minutes after arriving smelting temperature, cast with swage then.Prepare the alloy of 5 kinds of different components, tested its actual constituent by XRF, as shown in table 1 below.Wherein S1 and S2 sample are respectively Al-Yb and Al-Zr binary alloy, as contrast.

Table 1 technic metal composition

Sample	Design composition (wt.%)	The actual composition of Yb (wt.%)	The actual composition of Zr (wt.%)
				S1	Al-0.2Yb	0.25	/

S2	Al-0.28Zr	/	0.30
				S3	Al-0.2Yb-0.14Zr	0.21	0.15
S4	Al-0.2Yb-0.28Zr	0.19	0.27
				S5	Al-0.1Yb-0.28Zr	0.12	0.29

Example 2: 620 ± 10 ℃ of solid solutions 20 hours, shrend was annealed 3 hours every 25 ℃ between 150～575 ℃ then to room temperature to the alloy in the example 1.Fig. 1 has provided the hardness under the differing temps, can see that therefrom the S4 alloy reaches the about 50HV of highest hardness value at 400 ℃, far above the highest hardness value of S1 Al-Yb alloy.And its hardness of alloy that has added Zr is slower than Al-Yb alloy with temperature rising decline, illustrates that the thermostability of Al-Yb-Zr alloy is better than the Al-Yb alloy.In addition, facilitation phenomenon does not appear in the Al-Zr alloy, and this is because the precipitation process of Al-Zr alloy is too slow, and annealing in 3 hours is not enough so that it is separated out.

Example 3: S4 alloy in the example 1 was handled 20 hours 620 ± 10 ℃ of homogenizing, and shrend is to room temperature, then since 150 ℃ every 25 ℃ of annealing 3 hours, to 450 ℃ of end.Adopting cold rolling mode rolling reduction afterwards is 70%, rolling back is 200～575 ℃ 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, and the temperature alloy rigidity just has significant decline more than 375 ℃.Fig. 2 shows that the recrystallization temperature of alloy about 400 ℃, has good heat-resistant.

Claims

1. an Al-Yb-Zr alloy is characterized in that, has added the 0.07-0.25%(weight percent in the pure aluminum substrate) Yb, the 0.15-0.3%(weight percent) Zr, and other unavoidable impurities.

2. the solid-solution and aging heat treatment technology of the described Al-Yb-Zr alloy of claim 1, it is characterized in that may further comprise the steps, at first 620 ± 10 ℃ of solid solutions 20～30 hours, shrend subsequently is to room temperature, then 150 ℃～timeliness when waiting between (400～575) ℃, detailed process is behind 25 ℃ of 150 ℃ of every increases insulation 3h, up in (400～575) ℃ end.