Strengthening mechanisms in magnesium alloys containing ternary Ⅰ,W and LPSO phases  

作　　者：N.Tahreen D.F. Zhang F.S. Pan X.Q. Jiang D.Y. Li D.L. Chen 

机构地区：[1]Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario, MSB 2K3, Canada [2]College of Materials Science and Engineering, Chongqing University, Chongqing, 400045, China [3]National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing, 400044, China [4]Advanced Materials Research Center, ChongqingAcademy of Science and Technology, Chongqing, 401123, China [5]Faculty of Materials and Energy, Southwest University, Chongqing, 400715, China [6]Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 11-19, Canada

出　　处：《Journal of Materials Science & Technology》2018年第7期1110-1118,共9页材料科学技术（英文版）

基　　金：the Natural Sciences and Engineering Research Council of Canada (NSERC);Ontario Trillium Scholarships (OTS) program for providing financial support;financial support by the Premier’s Research Excellence Award (PREA);Canada Foundation for Innovation (CFI);Ryerson Research Chair (RRC) program;the Ministry of Science and Technology of China (2014DFG52810);National Great Theoretic Research Project of China (2013CB632200);National Natural Science Foundation of China (Project 51474043);Ministry of Education of China (SRFDR 20130191110018);Chongqing Municipal Government(CSTC2013JCYJC60001);Chongqing Science and Technology Commission (CSTC2011gjhz50001)

摘　　要：This study was aimed at identifying underlying strengthening mechanisms and predicting the yield strength of as-extruded Mg-Zn-Y alloys with varying amounts of yttrium （Y） element. The addition of Y resulted in the formation of ternary 1 （Mg3YZn6）, W （Mg3Y2Zn3） and LPSO （Mg12YZn） phases which subse- quently reinforced alloys ZM31 ＋ 0.3Y, ZM31 ＋ 3.2Y and ZM31 ＋ 6Y, where the value denoted the amount of Y element （in wt%）. Yield strength of the alloys was determined via uniaxial compression testing, and grain size and second-phase particles were characterized using OM and SEM. In-situ high-temperature XRD was performed to determine the coefficient of thermal expansion （CTE）, which was derived to be 1.38 x 10^-5 K^-1 and 2.35 x 10^-5 K^-1 for W and LPSO phases, respectively. The individual strengthening effects in each material were quantified for the first time, including grain refinement, Orowan looping, thermal mismatch, dislocation density, load-bearing, and particle shearing contributions. Grain refinement was one of the major strengthening mechanisms and it was present in all the alloys studied, irrespective of the second-phase particles. Orowan looping and crE mismatch were the predominant strengthening mechanisms in the ZM31＋0.3Y and ZM31 ＋ 3.2Y alloys containing I and W phases, respectively, while load-bearing and second-phase shearing were the salient mechanisms contributing largely to the superior yield strength of the LPSO-reinforced ZM31 ＋ 6Y alloy.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.This study was aimed at identifying underlying strengthening mechanisms and predicting the yield strength of as-extruded Mg-Zn-Y alloys with varying amounts of yttrium （Y） element. The addition of Y resulted in the formation of ternary 1 （Mg3YZn6）, W （Mg3Y2Zn3） and LPSO （Mg12YZn） phases which subse- quently reinforced alloys ZM31 ＋ 0.3Y, ZM31 ＋ 3.2Y and ZM31 ＋ 6Y, where the value denoted the amount of Y element （in wt%）. Yield strength of the alloys was determined via uniaxial compression testing, and grain size and second-phase particles were characterized using OM and SEM. In-situ high-temperature XRD was performed to determine the coefficient of thermal expansion （CTE）, which was derived to be 1.38 x 10^-5 K^-1 and 2.35 x 10^-5 K^-1 for W and LPSO phases, respectively. The individual strengthening effects in each material were quantified for the first time, including grain refinement, Orowan looping, thermal mismatch, dislocation density, load-bearing, and particle shearing contributions. Grain refinement was one of the major strengthening mechanisms and it was present in all the alloys studied, irrespective of the second-phase particles. Orowan looping and crE mismatch were the predominant strengthening mechanisms in the ZM31＋0.3Y and ZM31 ＋ 3.2Y alloys containing I and W phases, respectively, while load-bearing and second-phase shearing were the salient mechanisms contributing largely to the superior yield strength of the LPSO-reinforced ZM31 ＋ 6Y alloy.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关 键 词：Magnesium alloy I-phase W-phase LPSO phase Strengthening mechanism 

分 类 号：TG146.22[一般工业技术—材料科学与工程]