錸元素對鑄造Mar-M247超合金細晶顯微組織及拉伸性能影響之研究

The Effects of Rhenium Addition on the Microstructure and Tensile Properties of the Cast Fine-Grain Mar-M247 Superalloy

廖健鴻(J. H. Liao) ； 薄慧雲(H. Y. Bor) ； 魏肇男(C. N. Wei) ； 洪炎輝(Y. H. Hon) ； 鄭榮瑞(R. R. Jeng) ； 劉增豐(Z. F. Liu) ； 林於隆(Y. L. Lin) ； 鄭文興(V. S. Jeng)

《鑄造工程學刊》 34卷3期 (2008/09) Pp. 13-26

https://doi.org/10.29809/JTFS.200809.0002

摘要

本研究旨在探討錸元素對Mar-M247超合金細晶之顯微組織及機械性能影響之研究。研究結果顯示添加錸元素於Mar-M247超合金中，具有細化晶粒大小及γ'相之趨勢。當添加3wt.%錸元素時，晶粒內長條狀MC碳化物中的鉭、鈦及鉿會被大量的錸、鎢及鉻所取代，形成不連續之M23C6碳化物。部份σ相會在此不連續M23C6碳化物中成核。當錸增加至5wt.%時，此σ相會更成長針狀。拉伸研究結果顯示添加3 wt.%錸元素之Mar-M247超合金，具有最佳之抗拉強度及降伏強度。而添加5 wt.%錸元素時，會因針狀σ相大量析出，造成拉伸性能的下降。由破壞分析結果顯示當錸含量為0~3wt.%時，無論室溫或高溫拉伸測試，破壞模式皆屬沿晶破裂。當錸含量增加到5wt.%時，縫裂會沿著晶界及針狀σ相形成及成長。

關鍵字

細晶 ； 超合金 ； 錸 ； 碳化物

並列摘要

The effects of the Re additions on the microstructure and tensile properties of cast fine-grain Mar-M247 superalloy was investigated in this study. The results show that the Re additions were found to have beneficial effects to refine the grain sizes and γ' phase. As Re added up to 3 wt.%, Re, W, Cr replaced Ta, Ti, Hf within the rod type MC carbide, and then the MC carbide decomposed into discontinuous M23C6 carbide. The σ phases start to nucleate at the discontinuous M23C6 carbide. In addition, 5 wt.% Re additions could further promote the discontinuous M23C6 carbide to translated into Re, W, Cr-rich, needle-like σ phase. In this study, adding 3wt.% Re addition to MAR-M247 superalloy reveled the best tensile and yielding strength. On the contrary, in the 5wt.% Re addition, the drop in tensile properties is caused by the formation of σ phase. For the 0, 1 and 3 wt.% Re-containing alloys, the fracture is only along the grain boundary. In contrast, the fracture is along the grain boundary and the σ phase in the 5 wt.% Re alloy.

並列關鍵字

Fine Grain ； Superalloy ； Rhenium ； Carbide