Composition-dependent dynamic precipitation and grain refinement in Al-Si system under high-pressure torsion

作     者：Shenbao Jin Zhenjiao Luo Xianghai An Xiaozhou Liao Jiehua Li Gang Sha Shenbao Jin;Zhenjiao Luo;Xianghai An;Xiaozhou Liao;Jiehua Li;Gang Sha

作者机构：Herbert Gleiter Institute of NanoscienceSchool of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing210094 China School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneyNSW2006Australia Institute of Casting ResearchMontanuniversitat LeobenA-8700LeobenAustria 

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

年 卷 期：2021年第68卷第9期

页      面：199-208页

核心收录：

学科分类：0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 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：funded by the financial support of the National Natural Science Foundation of China (No.51751120 and No.51604156) support and the assistance of Material Characterization and Research Center of Nanjing University of Science and Technology 

主　　题：Al-Si alloys Composition effects Dynamic precipitation Solute segregation Grain refinement 

摘      要：Understanding composition effects is crucial for alloy design and development. To date, there is a lack of research comprehensively addressing the effect of alloy composition on dynamic precipitation, segregation and grain refinement under severe-plastic-deformation processing. This research investigates Al-x Si alloys with x = 0.1, 0.5 and 1.0 at.% Si processed by high pressure torsion(HPT) at room temperature by using transmission electron microscopy, transmission Kikuchi diffraction and atom probe tomography. The alloys exhibit interesting composition-dependent grain refinement and fast dynamic decomposition under HPT processing. Si atoms segregate at dislocations and Si precipitates form at grain boundaries(GBs) depending on the Si content of the alloys. The growth of Si precipitates consumes most Si atoms segregating at GBs, hence the size and distribution of the Si precipitates become predominant factors in controlling the grain size of the decomposed Al-Si alloys after HPT processing. The hardness of the Al-Si alloys is well correlated with a combination of grain-refinement strengthening and the decomposition-induced softening.