Mechanical properties of V-4Cr-4Ti strengthened by precipitation and cold rolling

V-4Cr-4Ti (NIFS-Heat-2) was strengthened in a thermo-mechanical process in which the alloy was solution-annealed at 1100 °C for 1 h and then aged at 600 °C for 20 h, followed by cold rolling at room temperature with a reduction of 20% in thickness. TEM observation indicated that extremely fine precipitates were produced during the aging. Precipitate coarsening did not occur during annealing the alloy at 750 °C due to the existence of high number density dislocations in the cold rolled alloy. High-temperature tensile tests showed this strengthening could remain effective up to 750 °C. Uniaxial thermal creep tests were conducted at 700-800 °C. Improvement in the property was observed at high stress level.