Microstructure and Phase Evolution of Ti-Al-C-Nb Composites Prepared by In Situ Selective Laser Forming

Kai Zhang; Shurui Li; Zhilong Yan; Zhiwei Xiong; Desti Dorion Likoundayenda Bakoutas; Tingting Liu; Wenhe Liao

doi:10.3390/ma15124351

Microstructure and Phase Evolution of Ti-Al-C-Nb Composites Prepared by In Situ Selective Laser Forming

Materials (Basel). 2022 Jun 20;15(12):4351. doi: 10.3390/ma15124351.

Authors

Kai Zhang¹, Shurui Li¹, Zhilong Yan¹, Zhiwei Xiong¹, Desti Dorion Likoundayenda Bakoutas¹, Tingting Liu¹, Wenhe Liao¹

Affiliation

¹ School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.

Abstract

In the present work, a novel Ti-Al-C-Nb composite was prepared using in situ selective laser forming (ISLF). The formation mechanism of the Ti-Al-C-Nb bulks, which were synthesized using elemental titanium, aluminum, and carbon (graphite) powders via ISLF techniques, was investigated. The results showed that the Ti₃Al and TiC phases were the dominant synthesis products during the chemical reactions, and these occurred during the ISLF process. The size of the fine nanoscale crystal TiC grains could reach 157 nm at an energy level of 60 J/mm³. The porous structure of the ISLF specimens was disclosed, and an open porosity of 20-44% was determined via the scanning speed and the laser power. Both the high dynamic viscosity and the reactions of the raw powders led to the generation of a considerable number of pores, whereas the specimen processed using 45 W and 100 mm/s possessed the lowest degree of open porosity.

Keywords: Ti3Al; TiC; in situ selective laser forming; porosity; reaction.

Grants and funding

This work was supported by the National Natural Science Foundation of China (Grant No. 52005262), Natural Science Foundation of Jiangsu Province (BK20190463), and Programme of Introducing Talents of Discipline to Universities (No. B18028).