Microstructure and mechanical properties of as-cast Ti-N alloy
(1.黑龙江省哈尔滨市哈尔滨工业大学材料科学与工程学院2.Department of Machine, Henan Polytechnic University, Jiaozuo 454000, China3.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: In-situ nitride reinforced Ti matrix composites with 0.045%-0.27%N（mass fraction） were produced by a casting process and the microstructure and the compressive mechanical properties of the as-cast composites were investigated in detail. The results show that the addition of N has significantly changed the microstructure of the as-cast Ti-N alloy. When N content ranges from 0.045% to 0.18%, the reinforcement is TiN 0.3 with mainly fine dendrite and small amount of thin flake structure and linear distribution. When the N content is increased to 0.225%, the reinforcement is changed from TiN 0.3 to Ti2N. For all kinds of the composites, the hardness, compressive strength and elastic modulus are higher than those of matrix pure Ti. In addition, the compressive strength, hardness and elastic modulus of the composites increase with the increase of Ti content. The fracture surface analysis results show that the composites fracture in a cleavage brittle model.
Key words: titanium alloy； nitride； cast microstructure； mechanical properties