预变形Mg-Nd合金时效析出行为的原子尺度  

Atomic-scale investigation of aging precipitation behaviors in pre-deformed Mg-Nd alloy

作　　者：郭文祥 谢红波 任玉平 秦高梧[1,2] Guo Wenxiang;Xie Hongbo;Ren Yuping;Qin Gaowu(Northeastern University School of Materials Science and Engineering,Shenyang 110819,China;Northeastern UniversityKey Laboratory for Anisotropy and Texture of Materials Ministry of Education,Shenyang 110819,China)

机构地区：[1]东北大学材料科学与工程学院,沈阳110819 [2]东北大学材料各向异性与织构教育部重点实验室,沈阳110819

出　　处：《材料与冶金学报》2024年第2期164-172,共9页Journal of Materials and Metallurgy

基　　金：国家自然科学基金青年基金项目(52101129).

摘　　要：使用球差校正的高角环形暗场扫描透射电镜(HAADF-STEM)系统研究了预变形Mg-20%Nd(质量分数)合金250℃等温时效2 h后的时效析出行为结果表明,预变形产生的位错促进了第二相的形核,导致高密度且有别于传统沿{101-0}α惯习面均匀分布的亚稳析出相的形成原子尺度的表征结果表明,合金内部形成的析出链主要由βS′相和β1相组成此外,析出链中还含有少量的β″和βH′相,以及βL′相这些片状或透镜状的βS′和β1相与α-Mg基体完全共格,且均具有一个{101-0}α的惯习面,但沿[112-0]α,[12-10]α和[2-110]α3个方向非均匀分布这些结果有望为形变调控合金的析出行为,提升合金力学性能提供理论指导.The precipitation behavior of the pre-deformed Mg-20%Nd(mass fraction)binary alloy isothermally aged at 250℃for 2 h has been systematically investigated by means of aberration-corrected high angle annular dark field-scanning transmission electron microscopy(HAADF-STEM)It is determined that the dislocations generated by pre-deformation facilitate the nucleation of secondary phases,leading to the formation of high density metastable precipitates which are different from the traditional uniform distribution along the{101-0}αhabit planesAtomic-scale observation shows that the precipitate-chains within the matrix consist mainly of theβS′andβ1 phasesIn addition,the precipitate-chains contain small amounts ofβ″andβH′phases,as well as theβL′phaseThese lamellar or lenticularβS′andβ1 phases are fully coherent with theα-Mg matrix,with a{101-0}αhabit planes,but are non-uniformly distributed along the three directions of[112-0]α,[12-10]αand[2-110]αThese results are expected to provide theoretical guidance for controlling the precipitation behavior of alloys via deformation to enhance the mechanical properties.

关 键 词：镁合金 变形 时效硬化 析出 HAADF-STEM 

分 类 号：TG141[一般工业技术—材料科学与工程]