Microstructural evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg-0.2Zr alloy during heat treatment

被引：53

作者：

Zhang, Xiaolong ^{[1
]}

Zhang, Liang ^{[1
]}

Wu, Guohua ^{[1
]}

Liu, Wencai ^{[1
]}

Shi, Chunchang ^{[1
]}

Tao, Jiashen ^{[1
]}

Sun, Jiangwei ^{[1
]}

机构：

[1] Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, Natl Engn Res Ctr Light Alloy Net Forming, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China

来源：

MATERIALS CHARACTERIZATION | 2017年 / 132卷

基金：

中国国家自然科学基金;

关键词：

Mechanical properties; Microstructure; delta '-Precipitate-free zones (PFZs); Electrical conductivity; MINOR SOLUTE ADDITIONS; PRECIPITATION KINETICS; CRYSTAL-STRUCTURE; T-1; PHASE; MG; AG; FRACTURE; TEMPERATURE; BEHAVIOR; STABILITY;

D O I：

10.1016/j.matchar.2017.08.027

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The microstructure, electrical conductivity and mechanical properties of cast Al-2Li-2Cu-0.5Mg-0.2Zr alloy during heat treatment were investigated. The results indicated that a population of secondary phases enriched along grain boundaries in as-cast studied alloy, most of which dissolved into the alpha-Al matrix after solution treatment. Profound enhancement in mechanical properties of the studied alloy was obtained after T6 heat treatment. TEM observations revealed competitive precipitation of T-1 (Al2CuLi) and S' (Al2CuMg) phases during ageing, while no theta ' (Al2Cu) phase was observed. The anomalous decrease in conductivity observed during ageing was attributed to the precipitation of T-1 phases. Fine delta ' (Al3Li) particles were homogeneously distributed after quenching, gradual coarsening of which was observed with prolonged ageing time. As ageing proceeded, the delta ' coarsened and delta '-Precipitate-Free Zones (PFZs) developed, resulting in diminishing ductility observed from as quenched to peak-aged state. Precipitation and continuous coarsening of T-1 phases kept on at the expense of gradual delta ' dissolution. The improvements of ductility observed in over-aged samples arose mainly from the presence of T-1, S' phases, Al-3(Li,Zr) composite precipitates and progressive delta ' dissolution. Moreover, continuous coarsening of T-1 and S' phases contributed primarily to the strength loss in over-aged studied alloy.

引用

页码：312 / 319

页数：8

共 48 条

[1]

Bagaryatsky Y.A., 1952, DOKL AKAD NAUK+, V87, P397

[2]

Bagaryatsky Yu.A., 1952, DOKL AKAD NAUK+, V87, P559

[3] A NEW METHOD FOR THE DETERMINATION OF THE PRECIPITATE-MATRIX INTERFACIAL ENERGY [J].