Heat Resistance of VT6 Alloy with and Without Aluminum-Chromium Diffusion Coatings at 500, 700, and 900 °C

I.Ya.Smokovich,
 
T.V.Loskutova,
 
V.G.Khizhnyak
 

Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2014, #01/02
http://www.materials.kiev.ua/article/1185

Abstract

This paper proposes a method for increasing the heat resistance of VT6 titanium alloy from 400 to 900 °C through complex saturation of its surface with aluminum and chromium in powder mixtures. Diffusion coatings formed on the alloy surface consist of titanium aluminides: Al3Ti, Al2Ti, AlTi and AlTi3, which have high thermal stability owing to adequate aluminum content needed to form Al2O3 surface film. The outer coating layer based on the Al3(Ti, Cr) phase contains 4.3–9.3 wt.% Cr, which may induce the formation of protective Cr2O3 oxide besides Al2O3. Increase in the microhardness of the VT6 alloy by a factor of 2 to 2.5, resulting from complex aluminum–chromium saturation, compared with the initial state should enhance its wear resistance.


ALUMINUM AND CHROMIUM SATURATION, DIFFUSION COATING, HEAT-RESISTANCE, MICROHARDNESS, OXIDATION, TITANIUM ALLOY, VT6