Evolution of the Microstructure and Mechanical Properties of a Ti35Nb2Sn Alloy Post-Processed by Hot Isostatic Pressing for Biomedical Applications

The HIP post-processing step is required for developing next generation of advanced powder metallurgy titanium alloys for orthopedic and dental applications. The influence of the hot isostatic pressing (HIP) post-processing step on structural and phase changes, porosity healing, and mechanical strength in a powder metallurgy Ti35Nb2Sn alloy was studied. Powders were pressed at room temperature at 750 MPa, and then sintered at 1350 degrees C in a vacuum for 3 h. The standard HIP process at 1200 degrees C and 150 MPa for 3 h was performed to study its effect on a Ti35Nb2Sn powder metallurgy alloy. The influence of the HIP process and cold rate on the density, microstructure, quantity of interstitial elements, mechanical strength, and Young's modulus was investigated. HIP post-processing for 2 h at 1200 degrees C and 150 MPa led to greater porosity reduction and a marked retention of the beta phase at room temperature. The slow cooling rate during the HIP process affected phase stability, with a large amount of alpha-phase precipitate, which decreased the titanium alloy's yield strength.

Automated summary

The influence of HIP post-processing on structural changes, porosity healing, and mechanical strength in powder metallurgy titanium alloys was investigated. Results showed that specific HIP processing conditions can significantly reduce porosity and retain the beta phase at room temperature.