Dynamic Compressive Properties and Failure Mechanism of the Laser Powder Bed Fusion of Submicro-LaB6 Reinforced Ti-Based Composites

Abstract

In this study, lanthanum hexaboride (LaB6) particle-reinforced titanium matrix composites (PRTMCs, TC4/LaB6) were successfully manufactured using the laser powder bed fusion (LPBF) process. Thereafter, the effect of the mass fraction of LaB6 on the microstructure and the dynamic compressive properties was investigated. The results show that the addition of LaB6 leads to significant grain refinement. Moreover, the general trend of grain size reveals a concave bend as the fraction increases from 0.2% to 1.0%. Furthermore, the texture intensity of prior β grains and α grains was found to be weakened in the composites. It was also observed that the TC4/LaB6 have higher quasi-static and dynamic compressive strengths but lower fracture strain when compared with the as-built TC4. The sample with 0.5 wt.% LaB6 was found to have the best strength–toughness synergy among the three groups of composites due to having the smallest grain size. Furthermore, the fracture mode of TC4/LaB6 was found to change from the fracture under the combined action of brittle and ductility to the cleavage fracture. This study was able to provide a theoretical basis for an in-depth understanding of the compressive properties of additive manufacturing of PRTMCs under high-speed loading conditions.

Editorial for the Special Issue on Laser Additive Manufacturing: Design, Materials, Processes, and Applications, 2nd Edition

“…The design of laser additive manufacturing covered in this Special Issue includes the material design (e.g., the high reflectivity and thermal conductivity multi-material 3D printing [ 22 ] and the microalloying for LPBF [ 20 ]) and the structural design (e.g., the triply periodic minimal-surface (TPMS) structure [ 18 ], the thin-walled main support structure [ 23 ]).…”

“…For the particle-reinforced titanium matrix composites (PRTMCs), Li et al [ 20 ] studied the impact of LaB6 content on the microstructure, quasi-static characteristics, and dynamic properties of titanium matrix composites, focusing primarily on the TC4 and TC4/LaB6 composites manufactured using LPBF. The sample with 0.5 wt.% LaB6 was found to have the best strength–toughness synergy among the three groups of composites due to having the smallest grain size.…”

“…This Special Issue covers a wide range of forming materials, including zirconium alloys [ 24 ], titanium alloys [ 20 , 23 ], steel [ 21 , 25 , 26 ], composites (e.g., electroless copper and carbon fiber [ 27 ]), and in particular, metallic multi-materials (e.g., copper/silver [ 22 ]), 4D printing materials (e.g., NiTi, smart materials for soft interactive hydrogel [ 19 ]).…”

“…As depicted in Figure 1 , this Special Issue featured a diverse array of topics, publishing a total of 11 contributions, comprising 10 original research articles and 1 review paper. After the high-quality reviewing process, four articles [ 18 , 19 , 20 , 21 ] were selected as Editor’s Choice. Each of them is briefly introduced below according to four aspects (i.e., design, materials, processes, and applications) of the laser additive manufacturing in this Special Issue.…”