Structure, processing, property correlation of metastable β titanium Ti-5Al-5Mo-5V-3Cr alloy

Abstract

This work reports the evolution of “Structure, Processing, Property Correlation of Metastable β Titanium Ti-5Al-5Mo-5V-3Cr alloy” as a function of different aging temperatures (625,725 and 775 °C) for 4 h subsequent to solution heat treatment. The hot-rolled sheet was heat treated in β phase field and then water quenched. The solution heat treated in β phase field and then water quenched samples were aged at 625, 725 and 775 °C for 4 h. The hot-rolled sample shows the presence of α and β phases. The β-solution heat treated in β phase field and then water quenched sample of the alloy exhibits single β phase. The intensities of X-ray peaks are varying and β (211) peak shows the maximum intensity. The maximum intensity can be ascribed to β (211) texture. The solution heat treated in β phase field and then water quenched sample aged at 625 °C for 4 h shows the very fine hexagonal α phase precipitates as compared to the samples aged at 725 and 775 °C for 4 h. The samples aged at 725 and 775 °C for 4 h has resulted in precipitate-free zones as a result of the rejection of Mo, V, and Cr (β stabilizing elements) during nucleation and growth of α precipitates along the β grain boundaries. The Vickers hardness values of the alloy increase from solution heat treated in β phase field and then water quenched to all aging temperatures. The sample aged at 625 °C for 4 h shows the maximum hardness which is due to the presence of fine α phase precipitates. This can be ascribed to typical precipitation hardening.