Al-Er-Hf alloy and heat treatment process thereof

An al-er-hf, processing technology, applied in the field of aluminum alloy materials and their heat treatment technology, can solve problems such as limited space and limited

Active Publication Date: 2014-04-16
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limited amount of solid solution of Er in the aluminum matrix during the conventional melting and casting process, the space for further improving its microalloying effect is limited.

Method used

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  • Al-Er-Hf alloy and heat treatment process thereof
  • Al-Er-Hf alloy and heat treatment process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] Example 1: An alloy ingot was prepared by melting in a graphite crucible and casting in an iron mold, and the raw materials used were pure aluminum and an intermediate alloy of Al6Er and Al4Hf. At a melting temperature of 790±10°C, first melt the aluminum ingot, then add the master alloy, after the master alloy is melted, degas hexachloroethane, stir, keep warm and let the elements in the melt distribute evenly Perform iron mold casting. Five alloys with different compositions were prepared, and their actual compositions were measured by XRF, as shown in Table 1 below. Among them, samples A1 and A2 are Al-Er and Al-Hf binary alloys, respectively, for comparison.

[0011] Table 1 Experimental alloy composition

[0012] sample

Embodiment 2

[0013] Example 2: After the alloy in Example 1 was solution treated at 635±10°C for 24 hours, it was water quenched to room temperature; then it was subjected to isochronic aging at 150~(425-600)°C for 3 hours, and samples were taken every 25°C. figure 1 The Vickers hardness of the alloy at different temperatures is given, from which it can be seen that the maximum hardness of the A4 alloy is about 62HV at 475°C, which is much higher than the maximum hardness value of the A1 Al-Er alloy. And with the addition of Hf, the hardness value decreases more slowly than that of Al-Er with the increase of temperature, which shows that the thermal stability of Al-Er-Hf alloy is better than that of Al-Er alloy. In addition, Al-Hf alloy did not show strengthening phenomenon, which is because the precipitation process of Al-Hf alloy is too slow and 3 hours annealing is not enough to make it precipitate.

Embodiment 3

[0014] Example 3: Alloys A1, A2, A3, and A4 in Example 1 were solution treated at 635±10° C. for 24 hours, then water quenched to room temperature; then isothermal aging treatment was performed at 350° C. figure 2 The hardness change curve of the solid solution alloy at 350°C isothermal aging is given. It can be seen from the figure that the hardness of the A4 alloy is the highest, reaching nearly 66HV, which is much higher than the rest of the alloy samples. The hardness value of the alloy added with Hf decreases more slowly than that of the Al-Er binary alloy sample as time goes on, which shows that its thermal stability has been greatly improved. However, the Al-Zr binary alloy aged at this temperature for 500 hours did not show strengthening phenomenon, and the alloy added with Er showed obvious age hardening, indicating that the presence of Er promoted the precipitation of Hf.

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Abstract

The invention relates to an Al-Er-Hf alloy and a heat treatment process thereof, and belongs to the technical field of alloy. The alloy is obtained by adding 0.12 to 0.25 weight percent of Er and 0.45 to 1.2 weight percent of Hf into a pure aluminium matrix. A solution and aging treatment process of the alloy comprises the following steps: firstly, carrying out solution treatment for 24 to 48h at a temperature of 635 plus and minus 10 DEG C and then carrying out water quenching to the room temperature; then carrying out isochronous aging for 3h on the solution alloy at intervals of 25 DEG C at a temperature of 150 to (425 to 600) DEG C; or carrying out isothermal aging treatment on the solution alloy at a temperature of 350 DEG C. According to the invention, Er and Hf are adopted to carry out multi-microalloying, so that the alloy not only has an obvious aging strengthening effect, but also has excellent high-temperature thermal stability; relative to an Al-Er alloy, the Al-Er-Hf alloy improves the aging strengthening effect and the high-temperature heat resistance; relative to an Al-Hf alloy, the Al-Er-Hf alloy enables the aging precipitation process to be obviously accelerated.

Description

technical field [0001] The invention belongs to the technical field of alloys, and in particular relates to an aluminum alloy material subjected to composite microalloying and a heat treatment process thereof. technical background [0002] Microalloying has always been an important means to tap the potential of alloys, improve the properties of alloys and further develop new aluminum alloys, and has become a hot spot in the material industry at home and abroad. In particular, the microalloying research of rare earth elements in aluminum alloys is a hot spot nowadays, among which the research on rare earth elements Sc is the most concentrated, and its microalloying effect is very significant, and a series of research results have been obtained. However, due to the high price of Sc, researchers searched for alternative elements with similar effects to Sc, and found that the rare earth element Er is similar to Sc, and can also form a strengthening phase of L12 structure with al...

Claims

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Application Information

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IPC IPC(8): C22C21/00C22F1/04
Inventor 聂祚仁吴浩文胜平高坤元黄晖
Owner BEIJING UNIV OF TECH
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