|GOUDA K. Mohammed||Egypt-Japan University for Science and Technology(E-JUST)|
|Spoluautoři Mohamed Abdel-Hady Gepreel, A. Abd El Moeium|
Metal or powder injection molding (MIM), which is derived from plastic injection molding, is great technique because their products are expected to have more homogeneous microstructure and avoids the density gradient if compared to the conventional press/sintering process. In this work, the microstructures and hardness change of Ti-Mn binary alloys produced by metal injection molding technique for biomedical applications are studied. The rule of Mn-content (5 – 15 mass% Mn) in the alloys was found very effective in controlling the stability of β-phase and, therefore, controlling the phase's constitution. The alloys in the as sintered condition (at 1100 °C for 8 hours) showed course α-phase and low hardness (300-320 HV). However, the β-phase was the predominant phase in all alloys when solution treated and showed higher hardness (330-360 HV). The ageing, after solution treatment, at temperatures 500 and 560 oC resulted in the precipitation of very fine α-phase (0.2-3.0 um) and, therefore, higher hardness (380-430 HV). Aging at lower temperatures resulted in finer α-phase precipitation with expected good ductility with low effect on the hardness. However, aging at lower temperature (400 oC) results in the precipitation of the isothermal w-phase with high hardness and low ductility. The alloy with low Mn-content showed high tendency to precipitate ω-phase when aged at such relatively low temperatures. Aging at the α-phase appearing zone for different times showed that the lower the aging temperature the longer the precipitation process window leading to higher control on the aging process to optimize the mechanical properties.