Study of phase constituents, microstructural evolution, tensile properties and micro-Vickers hardness of as-cast and water quenched Ti-Mo-Fe alloys

This study investigates phase constituents, microstructural evolution, tensile properties and micro-Vickers hardness of as-cast (AC) and water quenched (WQ) Ti-Mo-Fe alloys with varying molybdenum and iron contents. Three ternary alloys with Ti-8.6Mo-3.3Fe (TMF4), Ti-13Mo-2.2Fe (TMF5), and Ti-16.5Mo-1.1Fe (TMF6) compositions were designed from three theoretical methods, namely, electron per atom ( e/a ) ratio, the molybdenum equivalence ( Moeq ) and the Bo-Md . These alloys were cast using the arc melting furnace operating under inert atmosphere, followed by solution treatment and quenching. Different characterization techniques were used to analyse the microstructural evolution and phase constituents of the alloys XRD patterns of TMF4 and TMF5 samples in both AC and WQ conditions showed the presence of β and α″ phases whereas XRD peaks of TMF6 alloy in both conditions belonged to only β phase. Optical micrographs of all studied alloys in AC and WQ conditions showed only β equiaxed grains with different grain sizes. The EBSD phase maps of WQ TMF5 and TMF6 alloys revealed the presence of ω and β phases. It was illustrated that with an increase in β stability, the ultimate tensile strength (UTS) decreased slightly from 547 MPa to 540 MPa while elastic modulus of TMF5 and TMF6 decreased from 88 GPa to 74 GPa respectively.