Mechanical properties and precipitation evolution behavior of V–5Cr–5Ti alloy after cold rolling

Abstract

The mechanical properties and precipitation behavior of V–5Cr–5Ti alloy were investigated after 80% cold rolling and annealing by optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), and tensile testing. The TEM analysis revealed that the cold-rolled V–5Cr–5Ti alloy had two kinds of precipitates with an hexagonal close-packed(HCP) structure. The rectangular precipitate had the following lattice parameters: a=0.3041–0.3048nm, c=0.5153–0.5158nm, and c/a=1.69. The elliptically shaped precipitate had the following lattice parameters: a=0.3080–0.3082nm, c=0.5003–0.5009nm, and c/a=1.62. The other precipitates had a face-centered cubic(FCC) structure. The precipitates were broken into small spherical particles, which were arranged in the vicinity of the band structure. After annealing (1273 K×1h), the stable precipitates were formed by increasing the components of Cr and N. The yield strength of cold-rolled V–5Cr–5Ti alloy after annealing was 21.5% higher than that before cold rolling, and the yield ratio increased from 0.69 to 0.79.