Effect of Heat Treatment on Mechanical Properties of 17-4 PH Stainless Steel Gyroid Lattice Structures Manufactured by Selective Laser Melting and a Study on Weight Reduction Methods

Abstract

Weight reduction is critical in various engineering applications, as it directly impacts performance, efficiency, and overall cost-effectiveness. Topology optimization (TO) and lattice structures are effective methods for weight reduction, and such intricate designs are typically produced by additive manufacturing (AM). This research article presents an experimental investigation on the mechanical properties of uniform and gradient gyroid lattice structures manufactured through selective laser melting (SLM) using 17-4 precipitated hardening (PH) stainless steel (SS) material. The study focuses on analysing the effects of three different heat treatment processes on the compressive mechanical behaviour of the lattice structures using stress–strain graphs. Uniform lattices demonstrate superior mechanical properties by ensuring consistent structure stiffness and strength. Heat treatments decreased the grain size, resulting in increased yield strength for uniform and gradient structures compared to as-built samples. From the results, as-built samples showed higher plateau stress and energy absorption due to lower martensite content, leading to increased stress in the plateau region. Furthermore, different weight reduction methods such as TO, lattices, and the combination of TO and lattice can be studied and explained using an anchor bracket by utilising uniform and gradient-type sandwich lattice.