Effect of microstructure evolution on mechanical properties of a TiZrAlB alloy rolled by different processes

Abstract

For the development of structural titanium alloys with excellent mechanical properties, the effect of rolling temperature and cooling rate on phase composition, microstructure evolution, and mechanical properties in a full-α TiZrAlB alloy were investigated. Optical microscopy, scanning electron microscopy, transmission electron microscopy, and statistical analysis, were employed to further understand and control the processing-structure-property relationships. The experimental results of specimens rolled at a temperature range from the α to β phase region demonstrated a significant grain refinement trend as the rolling temperature increased, and the work hardening effect was stronger in specimens rolled at the α+β double phase region than those rolled in the single phase region. The high density of the original β grain boundaries also enhanced the mechanical properties when the specimens were rolled at temperatures around/above the β-transus temperature. The highest strength (σ0.2 = 1121 MPa and σb = 1387 MPa) with a failure elongation of 6.1% was obtained in 840 °C-rolling water-quenched specimens, however, the furnace cooling led to worsened mechanical properties. In sum, the variation in the mechanical properties of the series of rolled alloys was mainly ascribed to the microstructure evolution under the different rolling processes.