Microstructure, Tensile Properties, and Hot-Working Characteristics of a Hot Isostatic-Pressed Powder Metallurgy Superalloy

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• 作者：Litao Chang ; Wenru Sun ; Yuyou Cui ; Rui Yang
• 刊名：Metallurgical and Materials Transactions A
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：48
• 期：3
• 页码：1273-1287
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Characterization and Evaluation of Materials; Structural Materials; Surfaces and Interfaces, Thin Films; Nanotechnology;
• 出版者：Springer US
• ISSN：1543-1940
• 卷排序：48

文摘

A series of microstructure observation, tensile, and hot compression tests were conducted to investigate the variation of microstructure, tensile properties, and hot-working characteristics of a powder metallurgy (PM) superalloy with hot isostatic pressing (HIPing) temperature, to establish a basis for the parameter selection for PM superalloy preparation. The results show that the dendritic structure from the powder was not completely removed until the HIPing temperature is above the γ′ solvus; γ/γ′ eutectic formed when the powder particles were HIPed at 1533 K (1260 °C) or above. Prior particle boundaries (PPBs) were observed in alloys HIPed at 1513 K (1240 °C) and below; the PPB decoration is serious in alloys HIPed at 1483 K and 1513 K (1210 °C and 1240 °C), owing to melting and aggregation of the boride phase at the particle boundaries during HIPing; the PPBs were eliminated when the HIPing was done at 1533 K (1260 °C) or above. Tensile fracture mode of the alloy changes from inter-particle and transgranular mixed fracture to transgranular fracture with increasing HIPing temperature, which is in accordance with the change in precipitate distribution at the PPBs. The hot workability of alloy is poor for all combinations of HIPing/deformation conditions except for HIPing at sub-solvus temperature and deformation at low strain rates.