高温均匀化对Nb-Ti-Si-Cr基超高温合金组织和成分分布的影响

摘要

研究了不同均匀化温度对Nb-Ti-Si-Cr基超高温合金组织和元素分布的影响;结果发现随着高温均匀化处理温度的升高,硅化物的组织形貌由共晶首先转变为细长条状,随后长大为长条状,Laves相Cr2Nb的形貌由针状转变为粗大的不规则形貌,最后溶解.随着高温均匀化温度的升高,Ti在初生相Nbss中的含量呈现升高的趋势,而Cr在初生相Nbss中的含量呈现先升高后降低的趋势.%The effects of homogenizing temperature on the microstructure and distribution of chemical composi-tion of Nb-Ti-Si-Cr based ultrahigh temperature alloy were investigated. The results show that the previous Nbss/(Nb,X)5Si3eutectic colonies break into small (Nb,X)5Si3strip, then the strip became coarse with increase in heat-treatment temperature. The needle-like Laves Cr2Nb transform into needle-like Laves become coarse Laves blocks,and the previous Laves Cr2Nb particles dissolve into Nbss, much finer and crowded Cr2Nb platelets form during cooling with increase in heat-treatment temperature. Ti concentrations in primary Nbss phase decrease with increase in heat-treatment temperatures,and Cr concentration in primary Nbss phase increase firstly,then decrease with increase in heat-treatment temperatures.