Fabrication and mechanical properties of Ti2AlN/TiAl composite with continuous network structure
(1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu 610031, China;
2. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
3. School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Korea;
4. Department of Chemistry and Bioscience, Aalborg University, Aalborg, 9220, Denmark)
2. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
3. School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Korea;
4. Department of Chemistry and Bioscience, Aalborg University, Aalborg, 9220, Denmark)
Abstract: Nitrogen was introduced into TiAl pre-alloyed powder using high-temperature gas nitriding, and Ti2AlN/TiAl composites with a continuous network structure of the reinforced phase were prepared via spark plasma sintering. The results show that the hardness of the composite is significantly higher than that of TiAl alloy, and increases with the increase of nitriding time. The strengthening effect is originated from the synergistic effect of the solid-solution strengthening caused by the nitriding of the powder, the continuous network of the Ti2AlN phase with high hardness and elastic modulus, and the increase of dislocation density. Additionally, the compressive strength of the Ti2AlN/TiAl composites is lower than that of the TiAl alloy, which is related to a part of Ti2AlN particles that are directly formed after nitriding and excessive reinforcement content.
Key words: pre-alloyed powder; nitriding; Ti2AlN/TiAl composite; continuous network structure; microstructure; mechanical properties