Kinetics of reaction of commercial pure titanium and titanium alloys with O2, N2 and N2 (2nd Report)

Abstract

A series of experimental studies was performed on the kinetics of reaction of commercially pure Ti and Ti alloys with the gas phase H2 O2 and N2, and the Report 1 already dealt with the desorption of H2 from commercially pure titamium. This paper deals with the investigation on the desorption of H2 from Ti-5Al alloy and Ti-5Al-Cu alloy. Sponge titanium prepared by the Kroll process and alloying element were arc melted by the consumable electrodedouble-melting method, and the ingot was forged at 900° and machined to a rod of 7m/m in diameter, which was annaealed in argon atmosphere at 700°C and then degassed in vacuo of 1×10-4mmHg at 700°, 750, 800, 850 and 900°C. The evolved hydrogen was collected by means of a Bentells pump and measured by micro-Oelsat gas analysier. It was found that the logarithms of the concentration of hydrogen in metals were decreased in linear relation with time at any teperature in the same way as the case of commercially pure titanium, and from these relations the diffusion constaut D were calculated by Al Demarezs formula. Temperature dependences of D in the titanium alloys are offered as follows:D(Ti-5Al)=47.7exp(-36, 800/R·T)D(Ti-5Al-1Cu)=0.15exp(-25, 250/R·T)