The Effect of Cold Working on Creep Rupture Strength and Microstructure of Ni-23Cr-7W Alloy

• 作者: Keiji Kubushiro Kyohei Nomura Yoshiki Shioda Yoshinori Murata Youhei Sakakibara
• 来源期刊: 力学国际期刊(英文)
• 学科: 工学
• 关键词: A-USC HR6W Cold Working CREEP Strength GRAIN BOUNDARY SHIELDING Ratio M23C6 CARBIDE
• 年，卷（期）: 2017,（10）
• 页码范围: 283-295
• 页数: 13页
• 分类号: TG14

摘要

In order to clarify the reason why the creep rupture time of pre-strained Ni-23Cr-7W Alloy (HR6W) is longer than that of the non-pre-strained HR6W, microstructures of HR6W after a series of creep tests were investigated. The creep tests were conducted at 750°C, 90 and 100 MPa. In the pre-strained samples, the grain boundary shielding ratio by precipitates was larger than that of the non-pre-strained sample. In addition, in the pre-strained samples the size of the M23C6 carbide in the grains was finer than in the non-pre-strained sample. The W content in the M23C6 carbide in the pre-strained samples tended to be larger than in the non-pre-strained sample. Therefore, the Ostwald ripening of the carbide was delayed and the size of M23C6 carbide was thought to be fine for a long time. These observations show that creep strength in the pre-strained samples is higher than that of the non-pre-strained sample because of both precipitation strengthening inside of the grains and grain boundaries.