Structure evolution analysis in ultrafine-grained Zr and Nb-based beta titanium alloys

Abstract

Titanium beta type alloys with an ultrafine grain microstructure are interesting biomaterials that exhibit an excellent mechanical, physicochemical and biological properties. This study aimed to develop a new Ti14Zr16Nb and Ti23Zr25Nb (at. %) alloys. These materials were prepared by the combination of mechanical alloying and powder metallurgy approach with cold powder compaction and sintering or interchangeably hot pressing. The details of the processing method were presented for structure evolution analysis. The samples were characterized by an X-ray diffraction method, scanning electron microscopy observation, chemical composition determination, sinters porosity measurements and finally mechanical properties evaluation. The microscopic studies confirmed the ultrafine grain structure of the sinters. The mechanically alloyed Ti23Zr25Nb material upon sintering at 600 °C for 10 min led to the formation of the single β type phase structure. The present study has demonstrated that ultrafine structure for Ti14Zr16Nb and Ti23Zr25Nb systems proposed for medical implant applications can be fabricated by the application of hot pressing of mechanically alloyed powders at the temperature below α→β transus (600 °C).