镍基变形高温合金GH4350的微观结构特征和强化机制

Microstructure Characteristics and Strengthening Mecha-nism of Ni-based Wrought Superalloy GH4350: A Review

摘要:

GH4350（AEREX 350）是一种紧固件用镍基变形高温合金，最高使用温度可达750 ℃。GH4350具备高抗拉伸强度的同时，能抗疲劳、抗应力断裂、抗应力松弛和耐腐蚀，并具备低膨胀系数和缺口敏感性。该合金主要通过固溶强化以及γ′相沉淀强化，在γ′相析出的同时也会析出少量η相。研究指出，该合金的微观结构对热处理条件十分敏感，包括温度和时间，γ′相在某些热处理条件下会转变为η相，从而可能降低合金的性能。本文概述了GH4350的元素组成特点、受热处理调控的微观结构特征以及强化机制，旨在理解该合金性能优异的原因，并指导新型合金或性能优化型合金的开发，以进一步提高其承温能力。

Abstract:

GH4350 (AEREX 350) is a Ni-based wrought superalloy for high-performance fasteners, with a maximum service temperature of 750 °C. It has high tensile strength, fatigue resistance, stress rupture and relaxation resistance, corrosion resistance, low thermal expansion, and notch sensitivity. The high strength of GH4350 is largely derived through solid solution strengthening and the γ′ phase precipitation strengthening. During the precipitation of γ′ phase, a minor amount of η phase also precipitates. However, it is reported that the microstructure of alloy is sensitive to heat treatment parameters, including temperature and time. The γ′ phases can be transformed into η phases under certain conditions, potentially degrading the performance of the alloy. The chemical composition characteristics, heat treatment strategies, and strengthening mechanism of GH4350 were reviewed in this research, aiming to understand the factors behind its remarkable high-temperature performance, to guide the development of new alloys, and to further enhance its heat resistance.