High Temperature Tensile Behavior of Directionally Solidified MAR-M247 Superalloy

Abstract:

In this study, two heat treatment schemes were proposed to study the high temperature mechanical behavior of directionally solidified MAR-M247 superalloy. Two withdraw rates, namely, 60 and 180 mm/h were used to produce directionally solidified MAR-M247 specimens by the Bridgeman type furnace. Standard heat treatment (HT1) procedures are solution treatment at 1230°C for 2 h/ArC, then first aging at 980°C for 5 h/AC and followed by second aging at 870°C for 20 h/AC. Modified heat treatment (HT2) is solution treatment at 1260°C for 3 h/ArC and first aging at 980°C for 6 h/AC, then the same second aging procedure. Uneven size, shape and fusion-alike of gamma prime precipitates are observed after full HT1 scheme, whereas even size but fine gamma prime precipitates are observed in HT2 specimen. All three tensile properties (elongation to failure, ultimate tensile strength and yield strength) of HT2 specimens are higher than these of HT1 specimens either at room temperature 25°C or at high temperature 982°C for both withdraw rates. Uneven distribution of the γ′ precipitates attributes to the initial fracture of HT1 specimens.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 1153-1158
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.1153
• Online since: May 2014
• Authors: Hui Yun Bor*, Chao Nan Wei, An Chou Yeh, Wei Bin He, Huei Sen Wang, Chen Ming Kuo
• Keywords: Directional Solidification, Heat Treatment, MAR-M247 Superalloy, Tensile Behavior

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