PdW20包晶合金的凝固组织及相选择  

Phase Selection during Solidification of PdW20 Peritectic Alloys

作　　者：张吉明[1,2] 谢明[1,2] 杨有才[2] 陈永泰[1] 李爱坤[2] 王塞北[1] 胡洁琼[2] 王松[2] 

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]昆明贵金属研究所稀贵金属综合利用新技术国家重点实验室,昆明650106

出　　处：《贵金属》2014年第A01期72-76,共5页Precious Metals

基　　金：云南省应用基础研究项目(2011FA026);云南省对外科技合作计划省院省校科技合作项目(2012IB002);云南省创新团队(2012HC027);昆明市科技创新团队(2012-01-01-A-R-07-0005)

摘　　要：考察了凝固速率在50～1.8×10^3μm/s范围内的PdW20合金凝固组织及凝固速率对微观组织形态和领先相的影响。结果表明,三种不同凝固条件下的凝固组织由初生W相、包晶（Pd）相和固溶体Pd相组成。随着凝固速率增大,合金组织从树枝晶转变成等轴晶,晶粒大小快速减小。合金组织存在显微偏析,并且随着凝固速率增大,晶内与晶界上的成分差值减小。在3.2×10^2μm/s凝固速率下,观察到领先相W在进行包晶反应时不完全,还有部分W剩余。Effects of solidification microstructures and solidified rate on structural morphology and leading-phase of PdW20 alloy have been investigated with solidification rate in the range of 50～ 1.8×10^3μm/s. The results showed that three different solidification conditions of solidified structure were composed of the primary W phase, peritectic（Pd） phase and solid solution Pd phase. With the increasing of solidification rate, the alloy structure transformed from dendrite to equiaxed grain and crystalline size decreased rapidly. With the increasing of cooling rate, the alloy structure existed microsegregation, the composition contrast of the intragranular and the grain boundary decreased. At solidification rate of 3.2×10^2μm/s, we have observed that leading-phase W in peritectic reaction was incomplete, and parts of the W phase were remained.

关 键 词：PdW20合金 凝固速率 包晶反应 包晶相 

分 类 号：TG146.36[一般工业技术—材料科学与工程]