FGH98粉末冶金高温合金热变形过程中组织变化

THE MICROSTRUCTURE EVOLUTION OF FGH98 P/M SUPERALLOY AFTER HOT DEFORMATION

本文利用光学金相显微镜和扫描电镜观察了粉末冶金高温合金FGH98热等静压态锭坯经近等温锻造后的显微组织,研究了热变形对合金中原始颗粒边界(PPB)、粉末原始枝晶组织及晶粒度的影响。从动态再结晶和动态回复的角度分析了变形量对改善FGH98合金组织的作用,探索通过大变形量改善合金显微组织的途径。研究表明:经过三火锻造累积变形量达到75%的实验锭坯中PPB基本消除,获得γ′相均匀分布、晶粒尺寸为5μm的细晶组织。

The microstructure of P/M superalloy FGH98 had been observed after HIP and near isothermal forging by optical microscope and SEM,and then the effect of hot deformation on primary particle boundary（PPB）,grain size and dendritic structure was researched.How does the quantity of deformation（especially large deformation） affect the microstructure of FGH98 has been analysised based on dynamic recrystallization（DRX） and dynamic recovery（DRV） principle.The result shows that after three-order forging,the total quantity of deformation is up to 75%,and then the PPB in the billet has almost been eliminated,the grain size is as small as 5 μm and the γ′ phase distribute evenly in matrix.