一种镍基单晶合金热处理过程中的组织演变
Microstructure Evolution of a Ni-base Single Crystal Superalloy During Heat-treating
孙跃军1,葛艳辉2,张军3
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作者单位：1.辽宁工程技术大学 材料科学与工程学院 辽宁 阜新 123000；2.中平能化集团天工机械制造有限公司 河南 平顶山 467000；3.中国科学院力学研究所 北京 100190
中文关键字：镍基单晶合金；枝晶；固溶；时效；错配度
英文关键字： Ni-base single crystal superalloy; Dendrite; Solid solution; Aging; Mismatch
中文摘要：利用螺旋选晶法制备了镍基单晶合金，研究了热处理过程中合金的组织演变。研究结果表明：合金的铸态组织由枝晶组成，W偏析于枝晶干，Ti、Cr、Mo和Ta偏析于枝晶间，固溶处理可以消除铸态组织中的枝晶，减小成分偏析，固溶温度越高，粗大的γ′和γ/γ′共晶溶解的越完全。时效处理过程中，大尺寸的γ′发生粗化，小尺寸的γ′逐渐消失，时效温度越高，γ′粗化得越严重。热处理促进合金元素在γ和γ′中的均匀分布，减小了合金的错配度。
英文摘要：A Ni-base superalloy was prepared by using screw selecting crystal method. Microstructure evolution during heat-treatment of the alloy was investigated. Observation of microstructure showed that the as-casting microstructure was composed by dendrites. EDS analysis indicated that W partitioned in dendrite zone and Ti, Cr, Mo, Ta in inter-dendrite. Solid solution treatment decreased composition partitioning, and with the increasing of the temperature, coarsening γ′ and γ/γ′ eutectic solved completely. During the aging treating, the larger γ′ coarsened and the smaller γ′ disappeared gradually. Mismatch of the alloy decreased after heat-treating which due to the elements diffusing caused by heat-treatment.