Research on the microstructure and properties of the overhanging structure formed by selective laser melting

Abstract

Purpose This paper aims to analyze the different between matrix and overhanging structure and indicate the laws and mechanism of overhanging structure formed by selective laser melting (SLM). Design/methodology/approach This paper includes processing the matrix and overhanging structure with optimized parameters and analyzing the microstructure and properties of matrix and overhanging with OM, SEM, XRD etc. so as to analyze and reveal the laws and mechanism of overhanging structure formed by SLM. Findings The solidification of overhanging structure begins from the structure’s edge and extends to its center; the distribution of the Cr with a diameter of 250 nm in the Fe matrix is uniform; the grain in the overhanging structure is growing faster than the grain in the matrix. The overhanging structure mainly composed by austenite has no apparent layer. Moreover, the microhardness of the overhanging structure is 258.6-294.0 Hv0.3, smaller than the microhardness of the matrix which is 236.4-300.9 Hv0.3. Originality/value This paper clarifies how to manufacture overhanging structure and non-overhanging structure matrix with optimized parameters, analyzes the microstructures and compares the properties of both overhanging structure and non-overhanging structure “matrix”, so as to analyze the reasons for the forming of the overhanging structure, which in turn lauds basic data foundation for the theoretical studies in the future.

The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements

“…The building job can be modified by changing different parameters which indirectly and/or directly affect the quality of the melted area. The possibilities to modify the manufacturing process in the SLM technique has created the possibility to conduct scientific research at many scientific and industry facilities [10,11,12,13,14,15,16,17,18,19]. One of the most common topics is the analysis of the process parameters which influence on the mechanical properties of manufactured elements [20,21,22,23,24,25,26,27,28,29,30].…”

Channel design for 3D models with applications in powder-bed additive manufacturing

“…Additive manufacturing (AM), or 3D printing, is drawing intense attentions from the area of structural optimization. For example, Yang (2015) designed a novel kind of octahedral cellular structures with high strength, which can be used as the infill structures of 3D models for AM; Gorguluarslan et al (2017) proposed an optimization framework that considers the AM constraints for the design of lattice-based structures; Sun et al (2017) analyzed the difference between matrix and overhanging structures and studied the mechanism of overhanging structures formed by SLM; Xiao et al (2018) proposed the design rules in the lightweight design of an aluminum alloy antenna bracket using SLM; Zocca et al (2016) proposed a strategy for the densification of 3D printed structures by a thermally activated local melting; Li et al (2017) and Wei et al (2016) proposed a structural design of the gears and revolute joints for AM; to name just a few here.…”