Fabrication of in situ Ti_2AlN/TiAl Composites by Reaction Hot Pressing and Their Properties

• 作 者: 孙东立 SUN Tao WANG Qing HAN Xiuli GUO Qiang WU Gaohui
• 机 构: School of Materials Science and Engineering,Harbin Institute of Technology,
• 出 处: Journal of Wuhan University of Technology(Materials Science
• 发表日期: 2014年01期
• 关键词: TiAl powders remaining compressive precipitate powers pressing modulus hardness

Ti2AlN/TiAl composites with different volume fractions of reinforcement were successfully fabricated by hot-pressing sintering method(reaction hot pressing) using Ti, Al and TiN powders as starting materials. The synthesis process includes four stages: first, the reactions between Al and Ti powers and between Al and TiN powders respectively occur and result in TiAl3 phase; secondly, Al powders in the sample are exhausted; the remaining Ti cores react with TiAl3 layer to form Ti-Al intermetallics; moreover, a few Ti2AlN particles precipitate from the TiAl3 phase; thirdly, Ti-Al intermetallics react with the remaining Ti cores to form Ti3Al and TiAl phases. TiAl phase and original TiN powers are in direct contact each other; finally, the residual TiN powers react with TiAl phase and result in a plenty of Ti2AlN phase. Compared with TiAl matrix, the hardness, elastic modulus and high-temperature compressive strength of Ti2AlN/TiAl composite are improved obviously and they are all enhanced with increasing the volume fraction of Ti2AlN phase.

Ti2AlN / TiAl composites with different volume fractions of forging were successfully fabricated by hot-pressing sintering method (reaction hot pressing) using Ti, Al and TiN powders as starting materials. The synthesis process includes four stages: first, the reactions between Al and Ti powers and between Al and TiN powders respectively occur and result in TiAl3 phase; secondly, Al powders in the sample are exhausted; the remaining Ti cores react with TiAl3 layer to form Ti-Al intermetallics; moreover, a few Ti2AlN particles precipitate from the TiAl3 thirdly, Ti-Al intermetallics react with the remaining Ti cores to form Ti3Al and TiAl phases. TiAl phase and original TiN powers are in direct contact each other; finally, the residual TiN powers react with TiAl phase and result in a plenty of Ti2AlN phase. Compared with TiAl matrix, the hardness, elastic modulus and high-temperature compressive strength of Ti2AlN / TiAl composite are improved obviously and they are all enhanced with increasing the volume fraction of Ti2AlN phase.