Comparison of Bond Order, Metal d Orbital Energy Level, Mechanical and Shape Memory Properties of Ti-Cr-Sn and Ti-Ag-Sn Alloys

摘要

Bond order (Bo) and metal d orbital energy level (M_d) values were calculated for our recently developed Ti-(6,7)Cr-3Sn and Cr substituted Ti-(6,7)Ag-3Sn alloys developed in this study. Position of these alloys in the B_0-M_d phase stability map developed by Morinaga and co-workers was then determined. Phase constitution, mechanical and shape memory properties were co-related with the position of Ti-(6,7)Cr-3Sn and Cr substituted Ti-(6,7)Ag-3Sn alloy in the B_0-M_d phase stability map. Cr substitution with Ag has resulted drastic decrease in the bond order (B_0) and metal d orbital energy level (M_d) values, resulting drastic decrease in the strength, fracture strain and shape memory properties. Position of Ti-(6,7)Cr-3Sn alloys was within the twinning region of B_0-M_d phase stability map and these alloys exhibited good mechanical and shape memory properties due to stress induced martensitic transformation. It is concluded that position of developed Ti-Cr-Sn and Ti-Ag-Sn alloys in the B_0-M_d phase stability map not only affect the phase constitution but also the mechanical and shape memory properties.