アトマイズＴｉとＨＤＨ Ｔｉの混合粉末を用いたＴｉ‐４ｍａｓｓ％Ｃｒ成形体の圧粉成形性および焼結特性

Abstract

Crashed metallic Cr, atomized Ti and HDt1 Ti powders were mixed to the composition of Ti-4mass%Cr with varying the powder ratio of (HDH Ti/atomized Ti), and the strength of green compacts produced by the die-compaction method were evaluated, The sintering properties of green compacts were also discussed as a function of the volume fraction of HDH Ti powder.The green compacts without HDH Ti powder are sufficiently densified because the atomized Ti powder used has a wide distribution in the powder particle size. However, the bending strength of green compacts is very low, because the powder/powder interface is flat. The densification of compacts by sintering is little due to the large particle size, while there is a benefit that the shrinkage during sintering is very small (about 1%). The strength of green compacts is greatly enlarged with increasing the volume fraction of HDH Ti powder, because HDH Ti particles tangle each other. The size of HDH Ti powder is much lower than that of atomized Ti powder, therefore, the densification by sintering is also promoted with the increased volume fraction of HDH Ti powder. Since the shrinkage of compacts during sintering becomes larger by addition of HDH Ti powder, the adequate volume fraction of HDH Ti powder should be determined by taking the compactibility, sintering property, shrinkage of products besides mechanical properties into consideration.