http://scholars.ntou.edu.tw/handle/123456789/4651
標題: | Effects of Grain Boundary Microconstituents on Heat Affect Zone Cracks in a Mar-M004 Weldment | 作者: | Tai-Cheng Chen Yi-Hsin Cheng Leu-Wen Tsay Ren-Kae Shiue |
關鍵字: | gas tungsten arc welding;liquation crack;MC carbide;intermetallic compound;boride;Mar-M004 superalloy | 公開日期: | 四月-2018 | 卷: | 8 | 期: | 4 | 起(迄)頁: | 201 | 來源出版物: | Metals | 摘要: | Repair-welding of a cast Mar-M004 superalloy by gas tungsten arc welding was performed. Liquation cracks of the heat-affected zone (HAZ) in a Mar-M004 weldment were closely related to the presence of low-melting constituents along the solidified boundaries in the weld. The metal carbides (MC), M3B2 and M5B3 borides, Ni7(Hf,Zr)2 intermetallic compounds, and γ-γ′colonies were found at the interdendritic boundaries. Fine boride precipitates mixed with intermetallic compounds in lamellar form were more likely to liquate during repair-welding. The melting of borides and intermetallic compounds in 1180 °C/4 h treated samples confirmed the poor weldability of the Mar-M004 superalloy due to enhanced liquation cracking. In addition to boride formation, fractographs of liquation cracks revealed strong segregation of B element in carbides and intermetallics, which might further lower the solidus temperature of the repair weld. |
URI: | http://scholars.ntou.edu.tw/handle/123456789/4651 | ISSN: | 2075-4701 | DOI: | 10.3390/met8040201 |
顯示於: | 光電與材料科技學系 |
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