Microstructure and mechanical properties of a rapid directionally solidified Ti47Al alloy

The ingot of Ti47Al alloy was prepared by a newly developed rapid directional solidification, the microstructure and compressive properties of the ingot was observed and tested. The results show that the macrostructure consisted mainly of coarse columnar grains parallel to the axial direction, with the size of 0.5mm wide and 10mm in length. The direction of lamellar is almost perpendicular to the growth direction in the longitudinal section and no dendritic core is found. The average ultimate compressive strength of the specimens with grain growth parallel/perpendicular to the compressive direction is 1233.3 and 861.7 MPa respectively. The fracture mode for specimens with grain growth parallel to the compressive direction exhibits predominantly translamellar fracture, however, that for specimens with grain growth perpendicular to the compressive direction exhibits predominantly delamenation or interlamellar fracture.