时效处理对热挤压态Mg-Gd-Y-Sm-Zr合金组织和性能的影响  

Effect of aging on microstructure and properties of hot-extruded Mg-Gd-Y-Sm-Zr alloy

作　　者：兖利鹏 孙瑞雪 马秉馨 付靖 苏光 李全安[4] 郑鸿江 Yan Lipeng;Sun Ruixue;Ma Bingxin;Fu Jing;Su Guang;Li Quanan;Zheng Hongjiang(School of Materials Science and Engineering,Henan Institute of Technology,Xinxiang Henan 453003,China;Xinxiang Key Laboratory of Materials Processing Technology and Mould,Henan Institute of Technology,Xinxiang Henan 453003,China;School of Mechanical Engineering,Henan Institute of Technology,Xinxiang Henan 453003,China;School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang Henan 471023,China)

机构地区：[1]河南工学院材料科学与工程学院,河南新乡453003 [2]河南工学院新乡材料成形技术与模具重点实验室,河南新乡453003 [3]河南工学院机械工程学院,河南新乡453003 [4]河南科技大学材料科学与工程学院,河南洛阳471023

出　　处：《金属热处理》2025年第3期9-15,共7页Heat Treatment of Metals

基　　金：国基自然科学基金(52371108);河南省科技攻关项目(232102220091,242102240056);河南工学院博士科研启动金(KQ2426)。

摘　　要：用扫描电镜(SEM)、透射电镜(TEM)、电子背散射衍射(EBSD)、硬度试验和拉伸试验等研究了时效对热挤压态Mg-8Gd-4Y-1Sm-0.5Zr(GWS841)合金组织和性能的影响。结果表明,热挤压态GWS841合金的峰值硬度时效工艺分别为200℃×96 h、225℃×24 h和250℃×12 h,其中在200℃×96 h时效后峰值硬度和抗拉强度达到最大值。在200℃时效过程中,在α-Mg基体内稀土原子首先沿着〈1210〉_(α)晶向析出并形成黑色衬度条纹β′相,此时处于欠时效态;随着时效时间延长,β′相沿着〈1010〉_(α)晶向发生扩展,合金硬度也逐渐增大;时效96 h后,在(1120)α、(1210)α和(2110)α棱柱面内同时析出β′相,处于峰值时效态;时效120 h后,基体内的β′相长大形成梭状,晶界产生亚微米级的β相,此时处于过时效态。拉伸断裂机制为准解理断裂,断口组织由解理面、撕裂棱和韧窝组成。Effect of aging on the microstructure and properties of hot-extruded Mg-8Gd-4Y-1Sm-0.5Zr(GWS841)alloy was studied by means of scanning electron microscope(SEM),transmission electron microscope(TEM),electron backscatter diffraction(EBSD),hardness test and tensile test.The results show that the hardness of the hot extruded GWS841 alloy reaches the highest after aging at 200℃for 96 h,225℃for 24 h,and 250℃for 12 h,respectively.The peak hardness and tensile strength reach their maximum values after aging at 200℃for 96 h.During the aging process at 200℃,rare earth atoms first precipitate along〈1210〉_(α)crystal direction inα-Mg matrix to form a single black contrast stripe,β′phase,which is in the under aged state.As the aging time increases,theβ′phase expands along〈1010〉_(α)crystal direction,and the hardness of the alloy gradually increases.After aging for 96 h,β′phase precipitates simultaneously in the(1120)α、(1210)αand(2110)αcrystal planes,which is in the peak aged state.After aging for 120 h,theβ′phase in the matrix grows and forms a shuttle like shape,and sub-micronβphases are generated at grain boundaries,which is in the overaged state.The tensile fracture mechanism is quasi-cleavage fracture,and the fracture structure consists of cleavage planes,tearing edges,and dimples.

关 键 词：Mg-8Gd-4Y-1Sm-0.5Zr合金 时效处理 硬度 显微组织 强化机制 

分 类 号：TG166.4[金属学及工艺—热处理]