Park Young Keun, Nam Hyun Ji, Park Yong Ho, Lee Wookjin
School of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea.
Micromachines (Basel). 2024 Jan 24;15(2):176. doi: 10.3390/mi15020176.
This study investigates the effects of laser deposition and laser rescanning (LR) on the microstructure and mechanical properties of high-manganese steel (HMnS) deposited by laser-directed energy deposition (L-DED) comprising 24 wt.% Mn. Four types of laser deposition and LR strategies were investigated: unidirectional L-DED scanning without laser rescanning, L-DED scanning with 90° alterations in the laser scanning path on each layer without laser rescanning, unidirectional L-DED with laser rescanning in the same direction, and L-DED with laser rescanning with 90° alterations in the laser scanning path. The L-DED-processed HMnS had only a few small pores and exhibited a microstructure without any serious defects such as cracks. Additionally, a strong fibrous texture along the <101>/building direction of the fully austenite phase was found. The mechanical properties (microhardness and tensile strength) of HMnS were improved by the LR with a grain refinement effect and fine solidification cell size due to the significantly faster solidification rate in LR than that in L-DED.
本研究调查了激光沉积和激光重扫描（LR）对通过激光直接能量沉积（L-DED）沉积的含24 wt.%锰的高锰钢（HMnS）的微观结构和力学性能的影响。研究了四种类型的激光沉积和LR策略：无激光重扫描的单向L-DED扫描、每层激光扫描路径有90°变化且无激光重扫描的L-DED扫描、在相同方向进行激光重扫描的单向L-DED以及激光扫描路径有90°变化的激光重扫描的L-DED。经L-DED处理的HMnS只有少量小孔，且微观结构无任何严重缺陷，如裂纹。此外，在完全奥氏体相的<101>/构建方向上发现了强烈的纤维织构。由于LR中的凝固速率明显快于L-DED，通过具有晶粒细化效果和细小凝固晶胞尺寸的LR提高了HMnS钢的力学性能（显微硬度和抗拉强度）。
