【摘要】 用扫描电镜观察了预变形SiCp/ZA27复合材料在460℃等温热处理过程中的组织变化。结果表明,该复合材料的微观组织在此过程中经历了四个阶段:初期的快速粗化阶段、组织分离阶段、晶粒球状化阶段和最后的粗化阶段。当预变形量为20%时,初生晶由原来的具有不同方向的织构胞和粗短枝晶依次转变为少晶界的均匀组织、相互独立的细小多边形晶粒、15min时的球状晶粒和之后粗化了的球状晶粒。组织分离完成之后,晶粒的尺寸和形状系数随时间逐渐增大。当变形量为5%时,要获得球状晶必须处理80min以上,且所得晶粒尺寸大。更多还原

【Abstract】 The microstructure changes of the pre-compressed SiCp /ZA27 composite during isothermal heat treatment at 460℃ were observed by using scanning electron microscope. The results indicated that during this process, its microstructure experienced four stages: the initial coarsening stage, structure separation stage, spheroidization stage and the final coarsening stage. When the compression ratio was 20%, its primary phase changed from the initial texture structure cells with different orientations and coarsened short dendrites, which originated from the compressing of the as-cast developed dendrites, in turn into flat structure with few boundaries, independent small polygon grains, spherical grains (when heated for 15min) and coarsened spherical grains. After the structure separation completed, the grain size and shape factor increased with the increase of the heating time. When the compression ratio was 5%, it must be heated over 80min in order to achieve the globular grains, and the resulting grains were large.更多还原