(西安理工大学 陕西省电工材料与熔(浸)渗技术重点实验室，西安 710048)
摘 要: 采用真空熔炼工艺制备类K445高温合金，研究熔炼保温时间对其铸态组织及硬度的影响。结果表明，熔体保温时间对合金的相种类没有影响，合金均由树枝状γ基体、弥散分布于基体的γ′相、枝晶间的γ＋γ′共晶、γ′′相、MC碳化物、少量M3B2硼化物等强化相组成；但随熔体保温时间的延长，枝晶尺寸先减小后增大，MC碳化物含量先减少后增多，γ＋γ′共晶和γ
关键字: 类K445高温合金；熔体保温时间；显微组织；硬度
similar-K445 superalloy
（Shaanxi Province Key Laboratory for Electrical Materials and Infiltration Technology, Xi’an
University of Technology,Xi’an 710048, China）
Abstract:The effects of melt holding time on the microstructure and hardness of similar-K445 superalloy were investigated. The results show that melt holding time has no effect on the sorts of phases. The as-cast microstructure consists of MC carbide, eutectic γ′, γ′′, a spot of M3B2 borides in dendritic regions and secondary γ′ phase distributed in γ matrix. However, with increasing melt holding time, the sizes of dendrites as well as content of MC carbide increase before reduction, the contents of eutectic γ′ and γ′′ as well as the hardness of the alloys decrease before increase. When melt holding time is 30 min, the alloy gets the finest dendrites, the biggest contents of eutectic γ′ and γ′′, the least content of MC carbide and the highest hardness of HB 381.
Key words: similar-K445 superalloy; melt holding time; microstructure; hardness
