The University of Osaka · Materials Science
Professor Abdollah Bahador's research lab specializes in the development and processing of advanced titanium-based alloys and composites, with a focus on powder metallurgy, solidification behavior, and high-energy laser welding techniques. The lab investigates microstructure-property relationships in titanium matrix composites (TMCs), shape memory alloys (SMAs), and dissimilar metal joints, emphasizing grain refinement, phase transformation control, and defect mitigation during additive and fusion-based manufacturing. Key research directions include optimizing mechanical performance through alloying (e.g., W, Fe, Nb, Ta), controlling microstructure evolution during extrusion and sintering, and enhancing weldability of P/M-fabricated components using laser and GTAW processes. The lab also explores the role of processing parameters—such as defocusing distance, laser power, and welding speed—on porosity formation and phase stability in advanced titanium alloys.
Figures are computed from collected data and may differ slightly.
This study aims to improve the mechanical properties of a Ti–2Fe base alloy by adding W solute and performing hot extrusion at a high temperature (1000 °C). W was added at 0, 1, 2, and 3 wt% using the powder metallurgy route and homogenization heat treatment. The as-extruded materials predominantly consisted of α phase with different microstructure morphologies; Ti–2Fe and Ti–2Fe–1W contained equiaxed α grains, while Ti–2Fe–2W and Ti–2Fe–3W showed equiaxed+acicular and acicular shape, respective
This paper describes an investigation on the effect of using three different filler metals to weld two dissimilar metals namely, stainless steel 316L and low alloy carbon steel A516 gr 70. Manual Gas Tungsten Arc welding (GTAW) with three filler metals including ER 80S-Ni1, ER309L, ER NiCrMo-3 were selected to weld the two metals. Radiography and penetrant tests were performed on the welded metals to ensure the surface and internal soundness of the welds based on the tensile tests results, all t
Considering the high strength of titanium matrix composites (TMCs) at room and elevated temperatures, the aim of this study was to develop novel TMC Ti-4Fe-3W/2TiC (wt%) utilizing powder metallurgy and subsequent extrusion at different temperatures: the two-phase (α+β) and pure β phase regions. The TiC particle dispersion was almost identical in both composites with variation in the size distribution. However, there was a significant difference in the morphology of the α phase in the matrix. The
The influence of defocusing distance of the fiber laser welding on Ti-51at%Ni, Ti-28%atNb and Ti-30at%Ta shape memory alloys (SMAs) was investigated. These alloys were produced by powder metallurgy (P/M) and sintered by furnace and microwave processes. The experimental results showed that the furnace-sintered Ti-Ni welds have the maximum porosity density and the lowest weld quality. While, the microwave sintered alloys of Ti-Nb and Ti-Ta SMAs presented better weldability, even though porosities
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