1. Department of Mechanical Engineering, National University of Singapore, 117575 Singapore
2. Institute of Materials Research and Engineering (IMRE), A*STAR Agency for Science, Technology and Research, 138634 Singapore
3. NUS Centre for Additive Manufacturing, National University of Singapore, 117581 Singapore
4. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics Chinese Academy of Sciences, Shanghai 200050, P. R. China