Effect of Heating Temperature on Microstructures and Tribological Properties of Near βTi Alloy

The influence of heating temperature on microstructures and tribological properties of near βTi alloy Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe (wt.%) has been studied in this work. The volume fraction of primary α decreases gradually with solution temperature increasing, and as a result, the hardness and wear resistance are reduced. After aging treatment, the wear resistance of alloy is obviously improved. During aging the secondary α precipitates coarsen with aging temperature increasing. Secondary α precipitates are more effective to strengthen alloy than primary α. During friction process with stainless steel, the wear mechanisms of aged samples are mixture of abrasive wear, adhesive wear, and oxidation wear. Thermodynamic calculation by JmatPro software shows that the thickness growth rate (v) of α precipitates and aging temperature (T) obey the formula of v = 489.1936 × 10^0.0424 T, which is evidenced by experimental results. The transformation of α phase from β is corresponded with the BOR relationships, {110}_β//{0001}_α and [111]_β//[11 2¯ 0]_α.