基于等温热处理工艺制备细晶镁合金非枝晶组织  

Non-dendritic Structure of Fine Grained Magnesium Alloys Treated with Isothermal Heat Treatment

作　　者：王瑞权[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《热处理技术与装备》2009年第2期18-23,共6页Heat Treatment Technology and Equipment

基　　金：国家973计划资助项目(2007CB613700)

摘　　要：AZ91D镁合金通过Al-Ti-B变质处理获得细小的等轴晶。在固液两相区进行等温热处理,结合金相分析研究了组织的演化规律:等温热处理的初期,树枝晶经历了熔断、粒状化、球化和粗化的过程;随着加热温度的提高和保温时间的延长,共晶组织不断熔化成液相,液相体积分数逐渐增加,使液相薄膜包围着α相,α相由不规则形状向球状转化;α相的粗化和合并几乎同时进行,最终获得非常理想的半固态非枝晶组织。Microstructure of AZ91D magnesium alloy with fine equiaxed grain is obtained by adding Al-Ti- B modificator. The rule of microstructure evolution during the isothermal heat treatment in the range of liquid-solid two phase is investigated by ences dissolutionand granulation and optical microscop. The results show that the dendritic crystal experispheroidization and coarsening in the initial stages. With increasing the heating temperature and extending the isothermal holding time the eutectic structure melts down and its volume fraction of hquid increases gradually, which causes the liquid film to enclose the α phaseand and the shape of α phase to change from abnormity to sphericity. The coarsening and merging of α phase occur simultaneously. Finally the considerably ideal semi-solid non-dendritic structure is attained.

关 键 词：AZ91D合金 AL-TI-B 变质处理 等温热处理 

分 类 号：TG166.4[金属学及工艺—热处理]