L.X. Yin

Development of a new β Ti alloy with low modulus and favorable plasticity for implant material.

One of the most important development directions of the Ti and its alloys is the applications in medical field. Development of new Ti alloys with low elastic modulus and/or favorable biocompatibility plays an important role for promoting its application in medical field. In this work, a new β Ti alloy (Ti-31Nb-6Zr-5Mo, wt.%) was designed for implant material using d-electron alloy design method. Microstructure and tensile properties of the designed alloy after hot rolling (HR) and solution followed by aging treatments (SA) were investigated. Results show that the designed alloy is composed of single β phase. However, microstructural analysis shows that the β phase in the designed alloy separates into Nb-rich and Nb-poor phase regions. The Nb-rich regions in HR specimen are typical elongated fiber texture, but are equiaxed particles with several micrometers in SA specimen. Tensile results show that the designed alloy has low Youngs modulus of 44 GPa for HR specimen and 48 GPa for SA specimen which are very close to the extreme of Youngs modulus of bulk titanium alloys. At the same time, the designed alloy has favorable plasticity in term of elongation of 26.7% for HR specimen and 20.6% for SA specimen, and appropriate tensile strength over 700 MPa. In short, the designed alloy has low elastic modulus close to that of bone and favorable plasticity and strength which can be a potential candidate for hard tissue replacements.

Tribological Behavior and Wear Mechanism of TZ20 Titanium Alloy After Various Treatments

Abrasion is one of the most common failure forms of metals and alloys. The study of the friction and wear behavior of metals and alloys is greatly beneficial to improve their long life and safe service. The friction coefficient, weight loss, specific wear rate, and wear mechanism of Ti-20Zr-6.5Al-4V (TZ20) alloy after various treatments were investigated using a pin–disk-type wear apparatus at various normal loads. The wear results revealed that at a normal load, the friction coefficient steadily decreased, whereas the weight loss increased. By contrast, different specimens displayed distinct variation trends of specific wear rate with respect to the normal load. Further investigations indicated that the effects of hardness and toughness on the wear properties were markedly influenced by the normal load. The main characteristic of the abrasion surface gradually changed from grooves to plastic deformation as the normal load increased. The findings promote the practical application of TiZrAlV series alloys and expand wear theory.