EFFECT OF OXYGEN AND OXIDATION ON TENSILE PROPERTIES OF V-5CR-5TI ALLOY

Oxidation studies were conducted on V-5Cr-5Ti alloy specimens in an ai r environment to evaluate the oxygen uptake behavior of the alloy as a function of temperature and exposure time. The oxidation rates calcul ated from parabolic kinetic measurements of thermogravimetric testing and confirmed by microscopic analyses of cross sections of exposed spe cimens were 5, 17, and 27 mu m per year after exposure at 300, 400, an d 500 degrees C, respectively. Uniaxial tensile tests were conducted a t room temperature and at 500 degrees C on preoxidized specimens of th e alloy to examine the effects of oxidation and oxygen migration on te nsile strength and ductility. Microstructural characteristics of sever al of the tested specimens were determined by electron optics techniqu es. Correlations were developed between tensile strength and ductility of the oxidized alloy and microstructural characteristics such as oxi de thickness, depth of hardened layer, depth of intergranular fracture zone, and transverse crack length.