A method to determine main microstructural features influencing mechanical properties of two-phase titanium alloys

A new method to determine the major-minor sequence of microstructural features influencing mechanical properties of two-phase titanium alloys was proposed in a ternary microstructural system composed of equiaxed α phase, coarse α plates and residual β matrix in this investigation. The triplex heat treatment in (α+β) two-phase field was carried out on two-phase titanium alloys to change the relative contents of three microstructural features. The microstructure-property relationships described in the form of three-dimensional curved surface were established by interpolating property data and corresponding content data of these microstructural features in a stereoscopic triangular coordinate system. The major-minor sequence of microstructural features was determined by comparing the angles between contour lines of property surfaces and coordinate axes. The main microstructural feature influencing alloy׳s properties in a binary microstructual system was determined by superimposing the vertical section of a three-dimensional property surface along one coordinate axis and its corresponding major-minor sequence distribution. Validated using Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si alloy, the method is generally applicable to all two-phase titanium alloys or other alloys having a ternary microstructural system.