Connecting Solidified Microstructure with Compression Properties for Bulk Ti–Al Alloys with V Addition Conducted by Electromagnetic Levitation and First Principle

Abstract

Bulk Ti–Al based alloys with an approximate mass of 30 g are first prepared by electromagnetic levitation. The microstructures and the compression properties of Ti‐45%Al‐z%V alloys (z = 4, 8, and 12, atomic percent) at room and high temperatures are studied by experiments. The relationship between V content and the mechanical properties of γ and α2 intermetallics has been investigated by first‐principle calculations. It is clarified that V addition controls the phase contents and the microstructure characteristics. With the increase of V content, the microstructures of Ti‐45%Al‐4%V and Ti‐45%Al‐12%V are dominated by the phase transformations of α → γ and α → α2, respectively. Ti‐45%Al‐4%V alloy is mainly constituted of fine full lamellar γ phase while Ti‐45%Al‐12%V alloy is composed of coarsening lath α2 phase. Besides, the Young's modulus of Ti‐45%Al‐12%V alloy is smaller than that of Ti‐45%Al‐4%V alloy at 300 K, but the yield stress and ultimate compression stress are larger than that of Ti‐45%Al‐4%V alloy. The differences are attributed to the change of the main phase from γ to α2 and the mechanical properties of crystals changed by V addition. In addition, V addition changes the Young's modulus of α2 crystal from isotropy to anisotropy.