Microstructure and Mechanical Properties of Porous Commercially Pure Titanium

Abstract

The materials for bone implants have undergone much research, from using stainless steel to cobalt-chromium alloys to the current used material of titanium. However, titanium is still an imperfect material, with the elastic modulus of 90-110GPa, which is higher than that of cortical bone, which has an elastic modulus of 10-30GPa. Research was conducted to find a method which could reduce the elastic modulus of titanium to that of cortical bone. The research found that the space holder technique with the powder metallurgy method could achieve this, and after researching that ammonium bicarbonate served as a suitable space holder, the effects of parameters within the space holder technique was researched, which was used to generate the parameters used to produce samples for testing. After creating the samples to the set parameters, the samples underwent compression testing and hardness testing, from which stress-strain graphs and Vickers hardness were gathered. The results showed that the space holder technique was an effective method to create samples with elastic modulus close to that of cortical bone. It was also found that the optimal range of percentage of space holder was 30%-45%. The results showed that the samples have inconsistent mechanical behaviour, particularly for the 30% and 45% sample. For future works, the consistency of the mechanical behaviour, how close the materials behave to foamed materials and the linearity assumption between space holder percentage and elastic modulus should be tested.