Porous binary Ti-10Mo alloys were prepared using non-spherical titanium, molybdenum powders by the powder metallurgy (PM) space holder technique. Based on the three-dimensional analysis of porosity characteristics, a detailed assessment of the effects of porosity on mechanical properties and corrosion resistances in phosphate-buffered saline (PBS) was carried out. For comparison, PM-fabricated CP-Ti with 50.5% porosity sintered at 1200 °C for 2 h and dense Ti-10Mo alloy sintered at 1450 °C for 2 h (relative density is 97.2% and porosity is 2.8%) were studied simultaneously. The results show that with the space-holder volume contents rising from 63 to 79%, the open porosity and average pore size (d₅₀) increase remarkably, while the pore size distribution (d₁₀–d₉₀) tends to be stable at about 100 μm. The average pore sizes (d₅₀) of porous Ti-10Mo alloy can be controlled in the range of 70–380 μm. The PM-fabricated porous Ti-10Mo alloy can achieve a wide range of mechanical properties, with yield compression strength of 248.2–76.9 MPa, and elastic modulus of 6.4–1.7 GPa. In addition, the yield compression strength and the elastic modulus meet the linear regression and exponential formula, respectively. With the porosity of Ti-10Mo alloy increasing from 2.8 to 66.9%, the corrosion rate rises exponentially from 1.6 g/m²·day to 17.1 g/m²·day. In comparison to CP Ti with nearly the same porosity, Ti-10Mo alloy shows significantly higher corrosion resistance. As a result, the relationships between porosity and mechanical properties, corrosion resistances of Ti-10Mo alloys were established, which can be used as a design reference in material selection for orthopedic applications.

A biocompatible Ti-28Nb-35.4Zr alloy used as bone implant was fabricated through the powder metallurgy process. The effects of mechanical milling and sintering temperatures on the microstructure and mechanical properties were investigated systematically, before in vitro biocompatibility of full dense Ti-28Nb-35.4Zr alloy was evaluated by cytotoxicity tests. The results show that the mechanical milling and sintering temperatures have significantly effects on the density and mechanical properties of the alloys. The relative density of the alloy fabricated by the atomized powders at 1500 °C is only 83 ± 1.8%, while the relative density of the alloy fabricated by the ball-milled powders can rapidly reach at 96.4 ± 1.3% at 1500 °C. When the temperature was increased to 1550 °C, the alloy fabricated by ball-milled powders achieve full density (relative density is 98.1 ± 1.2%). The PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C can achieve a wide range of mechanical properties, with a compressive yield strength of 1058 ± 35.1 MPa, elastic modulus of 50.8 ± 3.9 GPa, and hardness of 65.8 ± 1.5 HRA. The in vitro cytotoxicity test suggests that the PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C has no adverse effects on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties and the net-shape manufacturability makes PM-fabricated Ti-28Nb-35.4Zr alloy a low-cost, highly-biocompatible, Ti-based biomedical alloy.

High Nb-containing TiAl alloy with a nominal composition of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (at %) was fabricated by metal injection moulding (MIM) technology with an improved wax-based binder. The critical powder loading and feedstock rheological behaviour were determined. The influence of sintering temperature on microstructures and mechanical properties of the sintered samples and their oxidation behaviour were also investigated. Results showed that a feedstock, with a powder loading of 68 vol % and good flowability, could be obtained by using the improved binder, and oxygen pick-up was lower than that of the sample prepared by using a traditional binder. The ultimate tensile strength (UTS) and plastic elongation of the sample sintered at 1480 °C for 2 h were 412 MPa and 0.33%, at room temperature, respectively. The 1480 °C-sintered sample consisted of γ/α₂ lamellar microstructure with the average colony size of about 70 µm, and its porosity was about 4%. The sintered alloy showed better oxidation resistance than that of the cast alloy counterpart.

Laser beam powder bed fusion (PBF-LB) enables the fabrication of complex rotational metallic components for aerospace applications, such as engine exhaust nozzles and combustion liners, but the localized thermal cycles inherent to the process often lead to residual stress accumulation and geometry-dependent distortion, particularly in low-stiffness and open structures. This study investigates the thermo-mechanical response of three representative 316L stainless steel rotational geometries—dumbbell-shaped, cylindrical, and drum-shaped—in both closed and open configurations using a transient, fully coupled thermo-mechanical finite element model validated by high-resolution three-dimensional deformation measurements. The results reveal pronounced geometry- and size-dependent distortion mechanisms: for closed structures, the drum-shaped geometry exhibits the largest radial contraction and stress concentration due to its larger characteristic size and lower stiffness, with a maximum deformation of approximately 0.14 mm, whereas the dumbbell-shaped and cylindrical geometries show smaller and more uniform deformations of about 0.09 mm and 0.12 mm; open configurations experience substantially amplified distortion, with both the magnitude and vertical location of bulging governed by geometric stiffness and substrate constraint, and the open drum-shaped structure reaching a maximum displacement of approximately 1.6 mm. These findings clarify how geometric size and stiffness control stress relaxation and shape stability in PBF-LB-fabricated rotational components and provide transferable guidance for geometry-informed design and distortion mitigation in high-precision additive manufacturing.

In this study, X-ray computed tomography was used to analyze powder binder separation in TC4 green bodies. Firstly, for the scanned results of the whole green body, because of the relative low resolution (36 µm), the powder binder separation can only be analyzed by using gray value distribution. Then, local regions (areas near the gate and the central parts) were scanned by using a much higher resolution (2.3 µm). Both of the volume fraction of powder content and gray value distributions indicate that powder particles tend to accumulate in the central parts. Finally, based on the results tested by using submicron resolution (0.8 µm), the effects of the volume and morphology of the powder particles on the powder binder separation were analyzed.