Synthesis of Multiphase Intermetallic Compounds in Ni-Al-Ti System by Mechanical Alloying

• Main Authors: Jiun Rung Shiu, 許俊榮
• Other Authors: Le-Chun Hsiung
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/81280264692520513860

碩士 === 國防大學中正理工學院 === 兵器系統工程研究所 === 93 === To achieve the elevated temperature resistance and the high strength alloy properties such as the elevated temperature stability and the strength, etc., three novel features have been conducted in this research. First, the designation of our alloy composition totally follows the principles of the alloy thermodynamic stability. We design our alloy respectively phase proportion according to the three-phase coexistence tie-triangle which connects gamma prime-beta-beta prime in the ternary phase diagram. In other words, we select the three tie-triangle vertex composition of the phase diagram to be the alloy respectively phase proportion and prepare each single phase intermetallics powders respectively. We then consolidate the three phase alloy. As long as the alloy is preserved below the selected constant temperature (below 900℃), the alloy will eventually reach the phase equivalence and the phase coexistence. Second, we utilize the property of the mechanical alloying (MA) that can generate nanocrystalline materials, even the amorphization, easily, to select the three alloys which their total composition are fallen in the inner of the tie-triangle. We then utilize the vacuum hot-pressed to concrete the shape after the mechanical alloying. Third, we first try to apply the gun shock-consolidated (dynamic compaction) to concrete the excellent densificated bulks to compare with the prior three phase alloy. In this paper, we also compare our experimental results with the multi-phase intermetallics on the shape of the powders and the bulks, identifying metastable crystalline phases (XRD), microscopic techniques (OM, SEM, TEM)、element analysis (EDX, ICP-AES), crystallize, ordered/disordered (DSC) thermal analysis, and the microhardness (HV).