日本金属学会誌

J. Japan Inst. Metals, Vol. 60, No. 8 (1996),
pp. 734-743

Stability of Refractory Oxides for Mold Material ofTi-6Al-4V Alloy Precision Casting

Ken-ichiro Suzuki, Sirou Watakabe and Koji Nishikawa

Technical Research Laboratories, Steel Development and Production Division, 1 Kawasaki-cho, Chuo-ku, Chiba 260, Japan

Abstract:

It has been proved that yttrium oxide has superior properties for the mold material in precision casting of Ti-6Al-4V alloy through basic studies on the reaction between one of plasma sprayed layers of oxides and liquid Ti-6Al-4V alloy during solidification. The reactivity estimated in terms of the maximum hardness and amount of oxygen absorbed in surface hardened layer formed at the surface of simple castings has good correlation with the high temperature stability of oxides evaluated by the standard free energy changes of formation of oxides, solution of oxygen and metallic constituents of oxides into liquid Ti-6Al-4V alloy. The hardness profile of the surface hardened layer has been quantitatively explained by the mechanism in which oxygen evolved from oxide instantaenouly after contacting with liquid Ti-6Al-4V alloy is absorbed and diffuses through liquid and solid layers of Ti-6Al-4V alloy castings.


(Received April 1, 1996)

Keywords:

precision casting, titanium, titanium alloy, near net shape technology, stability of oxide, yttrium oxide, surface hardened layer


PDF(Free)PDF (Free)     Table of ContentsTable of Contents

Please do not copy without permission.