铸态625合金均匀化处理优化研究

Optimisation of homogenisation treatment of cast 625 alloy

研究了1000~1250℃固溶处理对铸型625合金的微观组织和力学性能的影响。用扫描电镜、EDS、EPMA和DTA对合金的微观组织和凝固特性进行了研究。结果表明,该合金的凝固顺序应写为L→L+γ→L+γ+MC→L+γ+MC+γ/Laves→γ+MC+γ/Laves。在1225℃和1250℃溶液处理后,观察到Laves相的早期熔化。极限抗拉强度随溶液处理温度的升高而单调下降,屈服强度无显著变化。硬度值随固溶温度的升高而逐渐升高。晶粒大小也随温度的升高而增大。在1250℃溶液条件下,由于晶界处大量第二相熔化,微裂纹成核,断裂机理由跨晶模式转变为晶间模式。得出该合金的适宜溶液处理温度为1200℃。

The effect of solid solution treatment from 1000 to 1250℃on the microstructure and mechanical properties of cast 625 alloy was investigated.The microstructure and solidification properties of the alloy were investigated by scanning electron microscopy,EDS,EPMA and DTA.The results show that the solidification sequence of the alloy should be written as L→L+γ→L+γ+MC→L+γ+MC+γ/Laves→γ+MC+γ/Laves.early melting of the Laves phase was observed after solution treatment at 1225 and 1250℃.The ultimate tensile strength decreased monotonically with increasing solution treatment temperature and the yield strength did not change significantly.Hardness values gradually increased with increasing solid solution temperature.Grain size also increases with increasing temperature.At 1250℃solution,the fracture mechanism changes from a transgranular mode to an intergranular mode due to the nucleation of microcracks as a result of the melting of a large number of second phases at the grain boundaries.A suitable solution treatment temperature of 1200℃was obtained for this alloy.