【摘要】 采用光学显微镜和扫描电子显微镜研究了高温时效时间对DZ951合金组织及其持久性能的影响。结果表明,合金在1130℃高温时效时,碳化物由铸态时的骨架状变成块状,呈不连续状分布在晶界。随着保温时间的延长,γ′立方度降低,尺寸增加。保温6h时,γ′粗化形筏。合金在1130℃高温时效时,由于γ′部分固溶,并在随后的冷却过程中析出细小球形γ′相,随着保温时间的增加,细小γ′相的体积分数增多。DZ951合金在1100℃,60MPa的持久寿命随保温时间增加而降低,延伸率增加。γ′粗化形筏对合金持久寿命是不利的。更多还原

【Abstract】 Influence of high-temperature aging time on microstructure and stress rupture property of DZ951 superalloys was investigated by optical microscopy (OM) and scanning electronic microscopy (SEM).The results reveal that carbide changes from skeleton-like of as-cast alloy to block-like and discontinuously distributes in grain boundary when the alloy is aged at 1130 °C.γ′ cubicity decreases and the size of γ′ phase increases with the elongation of holding time at 1130 °C.γ′ coarsens and rafts when the holding time is 6 h.For solid solution of some γ′,fine and spherical γ′ phase precipitates during the following cooling process after 1130 °C aging treatment.The volume fraction of fine γ′ phase increases with prolonging the holding time.The stress rupture life of DZ951 alloy at 1100 °C/60 MPa reduces and the elongation increases with the prolongation of holding time.Coarsening and rafting of γ′ is deleterious to the stress rupture life for alloys.更多还原