Powder metallurgical processing of low modulus beta-type Ti-45Nb to bulk and macro-porous compacts

Year: 
2017
Month: 
9
Day: 
13
Pages: 
393-401
DOI: 
10.1016/j.powtec.2017.09.015
Author(s): 
Type: 
Journal Articles
Journal: 
Powder Technology
Volume: 
322
Abstract: 

Low modulus Ti-45Nb is a promising new alloy for bone implant applications owing to its excellent biocompatibility combined with bone-adapted mechanical performance. The present work demonstrates the applicability of powder metallurgical processing, i.e. hot pressing (HP) and spark plasma sintering (SPS), for the compaction of gas-atomized alloy powder under preservation of the main β-phase. Additional milling of the gas-atomized powder leads to irregular shapes and is effective for a significant refinement of the β-phase grains but causes increased oxygen contents. The yield strength of nearly fully dense samples increased from≈450MPa for samples made fromgas-atomized to ≈900 MPa for samples made from additionally milled powder while the Young's modulus remains low. Exemplarily, the production of macro-porous Ti-45Nb samples with 30% porosity by means of hot pressing with NaCl as space holder is demonstrated. At this porosity level Young's modulus values ≤5 GPa can be obtained. Also for macro-porous samples the use of additionally milled powder was beneficial for achieving increased strength values of ≈140 MPa. Mechanical performance data comparable to those of healthy spongy bone are obtained.