Influence of equal-channel angular pressing on aging precipitation in 7050 Al alloy

被引：26

作者：

Li, M. H. ^{[1
]}

Yang, Y. Q. ^{[1
]}

Feng, Z. Q. ^{[1
]}

Feng, G. H. ^{[1
]}

Huang, B. ^{[1
]}

Chen, Y. X. ^{[1
]}

Han, M. ^{[1
]}

Ru, J. G. ^{[2
]}

机构：

[1] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Peoples R China

[2] Beijing Inst Aeronaut Mat, Beijing 100095, Peoples R China

来源：

INTERMETALLICS | 2014年 / 55卷

关键词：

Precipitates; Strain-aging; Heat treatment; Electron microscopy; transmission; SEVERE PLASTIC-DEFORMATION; DYNAMIC PRECIPITATION; TEMPERATURE RISE; ZN; DUCTILITY; STRENGTH; CU; 7075-AL-ALLOY; ZONES; ECAP;

D O I：

10.1016/j.intermet.2014.07.005

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

7050 Al alloy was successfully processed by equal-channel angular pressing (ECAP) at room temperature (RT). The effect of ECAP on the subsequent aging precipitation behavior was investigated by using transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The results reveal that the kinds, spatial distribution and sizes of precipitates in the unECAPed and the ECAPed samples are different. ECAP accelerates the process of aging precipitation and results in the broadening of precipitate size distribution. ECAP can produce not only deformation heat but also internal defects such as excess vacancies and high density of dislocations when the sample passes through the main deformation zone. Deformation heat can lead to pre-precipitation, forming a small amount of GPII zones during ECAP processing. Strain-induced excess vacancies make solute segregation along dislocations by the mechanism of nonequilibrium segregation. High density dislocations mainly accelerate the process of aging precipitation. Besides, dislocations also induce the competition between homogeneous precipitation and heterogeneous precipitation on dislocations due to the flow of solutes and vacancies towards dislocations. (C) 2014 Elsevier Ltd. All rights reserved.

引用

页码：49 / 55

页数：7

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