[T14] High Temperature Materials

[16P-T14-03] Effect of High Temperature on Microstructure and Hardness of Ti-6Al-4Dy alloy by High Energy Ball Milling and Spark Plasma Sintering

*D. Lee¹, J. Ga¹, H. Kim¹, P. Kim¹, Y. Hong¹, S. Y. Chang¹ (1.Korea Aerospace University, Korea)

キーワード：High energy ball milling, SPS, Ti-Al-Dy alloy, high temperature hardness test, Microstructure

Ti-6wt%Al-4wt%Dy alloy powder was prepared by high energy ball milling and spark plasma sintering(SPS). A high energy ball milling was conducted in an argon atmosphere at 800rpm for 3h. Subsequently, the obtained powders were consolidated by SPS at 1373K for 15min under 50MPa in vacuum. The sintered body had approximately 99% in density and 6μm in grain size. From the XRD and TEM, the second phases, such as Ti₃Al, Al₃Dy and Ti₄Al₂₀Dy phases were confirmed, which was approximately 30 and 50nm in size by XRD and TEM, respectively. Micro-hardness was approximately 960Hv at room temperature and it decreased as temperature increased. XRD analysis of Ti-6Al-4Dy treated at 1173K revealed no discernible changes in peaks. However, the grain size increased from 6 to 10μm and the size of second phases also became larger to 32 and 52nm in using XRD and TEM, respectively. The obtained microstructural and mechanical characteristics of Ti-6Al-4Dy alloy at room and high temperatures are also compared with the Ti-6Al-4V alloy prepared by same processing.