Addressing the strength-ductility trade-off in a cast Al-Li-Cu alloy—Synergistic effect of Sc-alloying and optimized artificial ageing scheme

作     者：Jinshuo Zhang Guohua Wu Liang Zhang Xiaolong Zhang Chunchang Shi Xin Tong Jinshuo Zhang;Guohua Wu;Liang Zhang;Xiaolong Zhang;Chunchang Shi;Xin Tong

作者机构：National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix CompositesSchool of Materials Science andEngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Innovation Institute for MaterialsShanghai200444China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第96卷第1期

页      面：212-225页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Nos.51871148 and 51821001) the United Fund of National Department of Education and Equipment Development(No.6141A02033245) the National Key R&D Program of China(Grant No.2016YFB0301003)。 

主　　题：Cast Al-Li-Cu alloy δ’-PFZs Mechanical properties Cu-containing phases Microstructure evolutions 

摘      要：A dramatic improvement of strength and ductility of cast Al-2.5Li-1.5Cu-1Zn-0.5Mg-0.15 Zr alloy was obtained by the collaboration of Sc-alloying and optimized ageing scheme.Joint and independent influence of Sc-alloying and different ageing temperatures were investigated.The results revealed that a substantial increase was realized in the hardness of Sc-containing alloy,and the ageing response time was only influenced by ageing temperature.Coarse and heterogeneousδ (Al_(3)Li),wideδ -precipitation free zones(δ -PFZs),and a large amount of T_(1)(Al_(2)CuLi)precipitates were observed in Sc-containing alloy aged at 175℃,which resulted in superior yield strength and poor elongation.The Sc-containing alloy obtained an excellent combination of ductility(elongation=8.2%)and tensile strength(ultimate strength=565 MPa)suffered to 150℃ ageing for 64 h.The increase in the elongation was mainly due to the combined effect of grain refining,much finerδ ,and extremely narrowδ -PFZs(10 nm),while the higher strength was mainly attributed to the formation of Al_(3)(Sc,Zr,Li)composite particles and a large amount of S (Al_(2)CuMg)phase.However,the enhancement of the different ageing temperature(150℃ and 175℃)on the mechanical properties of the alloys without Sc addition was not obvious.