Influence of post-heat treatment on microstructure, mechanical, and wear properties of maraging steel fabricated using direct metal laser sintering technique

Abstract

The post-heat treatment of direct metal laser sintered parts is expected to have superior mechanical properties. Therefore, the purpose of the present study is to investigate the post-heat treatment effect on the microstructure, mechanical and wear properties of direct metal laser sintering processed maraging steel. Hence, a systematic methodology for microstructural characterization, mechanical properties, and tribological performance evaluation was performed. The microstructural examinations were performed using optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction technique. The micro-hardness and tensile properties were determined. The unidirectional sliding wear test was performed using a pin on disc wear testing machine for three different sliding velocities (0.8, 1.2, and 1.6 m/s) and three different normal loads (5, 10, and 15 N). The present study’s findings establish that the post-heat treatment techniques significantly altered the microstructural morphology and features. The results showed that the heat-treated sample had finer and non-continuous microstructure and more complex intermetallic precipitate phases, leading to higher hardness (∼64%) and higher tensile strength properties (70–80%) compared to the as-printed sample. The unidirectional sliding wear test results showed that the sliding velocity significantly affected frictional and wear characteristics of direct metal laser sintering processed maraging steel. The wear resistance of the heat-treated sample was three times higher than the as-printed sample, particularly at higher sliding velocities. In addition, the lower coefficient of friction values (∼24%) was observed for heat-treated sample compared to as-printed sample at higher sliding velocities. The post-heat treatment aids as an effective method to enhance mechanical properties of direct metal laser sintered parts and qualify them for tribological applications. The results endorse the suitability of the heat-treated direct metal laser sintered maraging steel in practical tool and die applications involving extreme tribological operating conditions such as higher sliding velocities and contact stresses.

Effect of build orientation on wear and erosion behavior of maraging steel processed by powder bed fusion using laser beam (PBF-LB)

“…Due to this reason, the wear rate increased even at higher loads in HT samples as shown in figure 8(b). The observation of small delamination lamella without significant delamination or wear debris in HT specimen is due to the increased hardness [32].…”

Influence of in-situ process parameters, post heat treatment effects on microstructure and defects of additively manufactured maraging steel by laser powder bed fusion—A comprehensive review

“…Repair and maintenance, Reduced waste and sustainability because of all of these variables working together, laser powder bed fusion is becoming increasingly significant in the field of additive manufacturing. As a result, this process has become a versatile and important technology that can be utilized in a variety of fields [50][51][52][53].…”

Hybrid surface characterisation of intra thin-walled Ti6Al4V surfaces produced by laser powder bed fusion technology

“…On the other hand, if the particle size ranges towards the lower end (about 1-10 μm), this increases in porosity or unmelted particles upon LPBF processing. Therefore, the particle size distribution significantly influences the porosity of the LPBF processed samples [23].…”