Microstructure and Toughness Characteristic of Nickel-Aluminum intermetallic compound added with Zirconia and Molybdenum

• Main Authors: Hung, Key Kun-Hui, 洪昆輝
• Other Authors: 蔡顯榮
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/38438869286611307428

碩士 === 國立臺灣科技大學 === 機械工程系 === 92 === The effects of molybdenum and zirconia mixtures on the microstructure and fracture toughness of NiAl intermetallic compound were studied. The 5wt.%, 10wt.%, 15wt.%, and 20wt.% molybdenum powders were mixed with the NiAl intermetallic compound and partially stabilized zirconia powders. The specimens were melted by arc melting in a argon atmosphere. The microstructural evolution of these alloys was examined by optical microscopy, scanning electron microscopy, X-ray diffraction. The composition of these alloys was examined by electronic probe micro-analysis (EPMA). The mechanical property measurements by means of hardness. The toughness characteristic of these alloys was examined by crack’s lengths measuring and crack’s images observing. Experimental results show that the solidification microstructure may be classified into three categories, the NiAl-rich matrix, Zr-rich structure, and Mo-rich dendritic. The fine Molybdenum-rich structure existed with addition of Mo. The addition of 20wt.% Mo in NiAl-ZrO2 alloy provided significant improvement in fracture toughness, duo to crack deflection, crack branching and local plasticity deformation.