Microstructure, Mechanical Properties and Fracture Behavior of Micron-Sized TiB2/AlZnMgCu(Sc,Zr) Composites Fabricated by Selective Laser Melting

Peng Yin; Yantao Liu; Zhuoheng Liang; Wei Pan; Shuobing Shao; Yongzhong Zhang

doi:10.3390/ma16052112

Microstructure, Mechanical Properties and Fracture Behavior of Micron-Sized TiB₂/AlZnMgCu(Sc,Zr) Composites Fabricated by Selective Laser Melting

Materials (Basel). 2023 Mar 6;16(5):2112. doi: 10.3390/ma16052112.

Authors

Peng Yin^{1

2

3}, Yantao Liu^{1

2

3}, Zhuoheng Liang^{1

2

3}, Wei Pan^{1

2

3}, Shuobing Shao^{1

2

3}, Yongzhong Zhang^{1

2

3}

Affiliations

¹ National Engineering & Technology Research Center for Non-Ferrous Metals Composites, GRINM Group Corporation Limited, Beijing 101407, China.
² Grinm Metal Composites Technology Co., Ltd., Beijing 101407, China.
³ General Research Institute for Nonferrous Metals, Beijing 100088, China.

Abstract

In this paper, micron-sized TiB₂/AlZnMgCu(Sc,Zr) composites were fabricated by selective laser melting (SLM) using directly mixed powder. Nearly fully dense (over 99.5%) and crack-free SLM-fabricated TiB₂/AlZnMgCu(Sc,Zr) composite samples were obtained and its microstructure and mechanical properties were investigated. It is found that the laser absorption rate of powder is improved by introducing micron-sizedTiB₂ particles, then the energy density required for SLM forming can be reduced, and the densification can finally be improved. Some crystalline TiB₂ formed a coherent relationship with the matrix, while some broken TiB₂ particles did not, however, MgZn₂ and Al₃(Sc,Zr) can perform as intermediate phases to connect these non-coherent surfaces to aluminum matrix. All these factors lead to an increase in strength of the composite. The SLM-fabricated micron-sized TiB₂/AlZnMgCu(Sc,Zr) composite finally shows a very high ultimate tensile strength of ~646 MPa and yield strength of ~623 MPa, which are higher than many other aluminum composites fabricated by SLM, while maintaining a relatively good ductility of ~4.5%. The fracture of TiB₂/AlZnMgCu(Sc,Zr) composite is occurred along the TiB₂ particles and the bottom of the molten pool. This is due to the concentration of stress from the sharp tip of TiB₂ particles and the coarse precipitated phase at the bottom of the molten pool. The results show that TiB₂ plays a positive role in AlZnMgCu alloys fabricated by SLM, but finer TiB₂ particles should be studied.

Keywords: Al3(Sc,Zr); TiB2/AlZnMgCu(Sc,Zr) composites; fracture behavior; heterostructure; selective laser melting.

Grants and funding

This research received no external funding.