机械合金化Cu-C-Ti复合粉末的组织特征

Characteristics of Cu-C-Ti Mixed Powders by Mechanical Alloying

采用扫描电镜、X射线衍射分析等实验手段 ,研究了Cu 2 %C 8%Ti(质量分数 )混合粉末在机械合金化 (MA)时的组织形态特征以及微观结构的变化规律。结果表明 ,Cu C Ti混合粉末经 48hMA后形成了Cu基过饱和固溶体 ;96hMA后 ,部分Ti、C溶质元素脱溶析出并且发生机械化学反应而生成碳化物TiC。MA导致复合粉末细化与扁平化 ,自由表面、晶界、亚晶界以及位错等晶体缺陷的急剧增加而明显地降低了扩散激活能 ,它是形成过饱和固溶体和促进第二相析出的主要原因。

The characteristics of morphologies and changes of the microstructures in mechanically alloyed (MA)[Cu C Ti(mass ratio)=90∶2∶8]mixed powders were investigated by using SEM observation and X ray diffraction (XRD) analyses. The results show that Cu, C and Ti mixed powders MA for 48 h forms the Cu-based super-saturated solid solution; after MA for 96 h the partial solute elements of Ti and C precipitate, meanwhile, the mechanochemical reactions take place and the carbide TiC form. The composite powders after MA are fine and flat. The formed defects such as free surface, grain boundary, sub grain boundary and dislocation decrease diffusion activity energy, which is the important reason for developing super saturated solid solution and promoting the second phase precipitation.