The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue cr...The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.展开更多
Ti-Ni-Mo-Si composite coating was fabricated on mild steel by reactive braze coating process with Ti61. 9Ni24. 6Si4. 411409.1 （ wt. % ） powders as the raw materials. Microstr^cture of the coating was characterized b...Ti-Ni-Mo-Si composite coating was fabricated on mild steel by reactive braze coating process with Ti61. 9Ni24. 6Si4. 411409.1 （ wt. % ） powders as the raw materials. Microstr^cture of the coating was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy and micro-hardness tester. Results indicate that the Ti-Ni-Mo-Si composite coating is metallurgically bonded to the mild steel substrate and has high hardness. The microstructure of the coating consists of the reinforcement of Ti5 Si3 and Mo9 Ti4 particles and the matrix of eutectic NiTi2. Due to the poor wettability of NiTi2 liquid at low temperature, TisSi3 and Mo9 Ti4 do not uniformly distribute in the NiTi2 matrix.展开更多
The effects of directional solidification parameters and the coupling of directional solidification parameters and alternating electromagnetic fields on separation and enrichment of the C54–TiSi2 phase were investiga...The effects of directional solidification parameters and the coupling of directional solidification parameters and alternating electromagnetic fields on separation and enrichment of the C54–TiSi2 phase were investigated in a directionally solidified hypoeutectic Ti–65 wt.%Si alloy.The results indicated that by increasing the pull-down velocity at a given position within the ingot,the cooling rate,growth rate,and temperature gradient of ingot could be increased.At a pull-down velocity near 5μm/s,the temperature gradient,cooling rate,and growth rate decreased with increasing the thickness of the C54–TiSi2-rich layer.Electromagnetic fields enhanced mass transfer at pull-down velocities of 5,10,15,and 20μm/s,with resulting enriched layer thicknesses of 15,10,10,and 5 mm,respectively.By increasing the percentage of Ti in the Ti–Si alloy from 25 to 35 wt.%,the thickness of the C54–TiSi2-rich layer was increased from 2.5 to 3.3 cm.However,the maximum C54–TiSi2 content obtained experimentally in this layer decreased from 92.06 to 79.49 mass%.展开更多
文摘The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.
文摘Ti-Ni-Mo-Si composite coating was fabricated on mild steel by reactive braze coating process with Ti61. 9Ni24. 6Si4. 411409.1 （ wt. % ） powders as the raw materials. Microstr^cture of the coating was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy and micro-hardness tester. Results indicate that the Ti-Ni-Mo-Si composite coating is metallurgically bonded to the mild steel substrate and has high hardness. The microstructure of the coating consists of the reinforcement of Ti5 Si3 and Mo9 Ti4 particles and the matrix of eutectic NiTi2. Due to the poor wettability of NiTi2 liquid at low temperature, TisSi3 and Mo9 Ti4 do not uniformly distribute in the NiTi2 matrix.
基金This research was supported by the National Natural Science Foundation of China(No.U1702251)Special Funds of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(Grant No.CNMRCUTS1604)+2 种基金the Program for Innovative Research Team in University of Ministry of Education of China(No.IRT_17R48)Key Laboratory of Comprehensive Utilization of Vanadium and Titanium Resources in Sichuan Province(2019FTSZ06)the PhD Fund of Panzhihua University,and Funded by the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization.
文摘The effects of directional solidification parameters and the coupling of directional solidification parameters and alternating electromagnetic fields on separation and enrichment of the C54–TiSi2 phase were investigated in a directionally solidified hypoeutectic Ti–65 wt.%Si alloy.The results indicated that by increasing the pull-down velocity at a given position within the ingot,the cooling rate,growth rate,and temperature gradient of ingot could be increased.At a pull-down velocity near 5μm/s,the temperature gradient,cooling rate,and growth rate decreased with increasing the thickness of the C54–TiSi2-rich layer.Electromagnetic fields enhanced mass transfer at pull-down velocities of 5,10,15,and 20μm/s,with resulting enriched layer thicknesses of 15,10,10,and 5 mm,respectively.By increasing the percentage of Ti in the Ti–Si alloy from 25 to 35 wt.%,the thickness of the C54–TiSi2-rich layer was increased from 2.5 to 3.3 cm.However,the maximum C54–TiSi2 content obtained experimentally in this layer decreased from 92.06 to 79.49 mass%.
