The Effect of Hot Isostatic Pressing on Surface Integrity, Microstructure and Strength of Hybrid Metal Injection Moulding, and Laser-Based Powder Bed Fusion Stainless-Steel Components

Abstract

Hybrid manufacture of components by combining capabilities of replication and additive manufacturing processes offer a flexible and sustainable route for producing cost-effectively small batches of metal parts. At present, there are open issues related to surface integrity and performance of such parts, especially when utilising them in safety critical applications. The research presented in this paper investigates the ductility amplification of hybrid components produced using metal injection moulding to preform and then build on them customisable sections by laser-based powder bed fusion. The properties of such hybrid components are studied and optimised through the use of non-conventional post treatment techniques. In particular, hot isostatic pressing (HIP) is employed to improve mechanical strength and to produce hybrid components that have consistent properties across batches and throughout the samples, minimising microstructural heterogeneities between fabrication processes. Thus, the investigated post-processing method can offer an extended service life of hybrid components, especially when operating under severe conditions. The optimised post treatment was found to increase the hybrid components’ strength compared to as-built ones by 68% and ~11% in yield strength (YS) and ultimate tensile strength (UTS), respectively. Subsequently, leading to a great pitting resistance, thus, making HIP samples suitable for corrosive environments. The advantages of the HIP treatments in comparison to the conventional heat treatment of hybrid components are discussed and also some potential application areas are proposed.

Innovative Material Processing Techniques in Precision Manufacturing: A Review

“…The integration of these processes presents substantial opportunities for advancing material utilization, part complexity, and quality management in functional parts (Flynn et al, 2016). Furthermore, hybrid manufacturing systems have been shown to offer a flexible and sustainable approach for producing cost-effective small batches of metal parts (Mehmeti et al, 2021). The benefits of hybrid manufacturing in precision applications are evident in its ability to produce parts more efficiently and productively by combining two or more technologies (Avram et al, 2021).…”

Surface integrity of hybrid CM247LC/Inconel 718 components produced by laser-directed energy deposition

“…The energy penetration from the laser source had a significant impact on the vanishing of the beneficial compressive stresses after the initial machining. Therefore, it is apparent that the heating from laser irradiation has had substantial effects into the Inconel 718 preform and thus it can be stated that the surface preparation process, such as machining or grinding, has a limited or marginal effect on residual stresses into the deposited material [53]. In particular, the heat affected zone at the interface triggers a redistribution of dislocation densities that consequently affects the subsurface below the high shear zone of the machined material, as shown in Fig.…”

Surface Roughness, Topography, Accuracy, Chip Formation Analysis & Investigation of M390 and M398 Steels after Hard Machining

“…They found out that while using water-based dielectrics in this process there is a higher tensile residual stress in comparison with the using of the chemical Wire-EDM process, but altogether the W-EDM process affects in very negative way to surface integrity. Mehmeti et al [13] tried to get best surface integrity on the products produced by MIM (Metal Injection Moulding) and L-BPF (Laser-Based Powder Bed Fusion) processes and followed by HIP. They were successful and produced structures nearly without pores or another defect.…”