Fatigue Crack Growth Behaviour of Cobalt-based and Nickel-based Superalloy Processed by Selective Laser Melting
type: CreativeWork
description: The production of cobalt-based and nickel-based superalloys via Selective Laser Melting (SLM) has been successfully applied in low-mass production, particularly in producing components/equipment for the spacecraft and medical industries. SLM technique allows complex and customised parts to be produced rapidly, replacing the traditional process of investment casting and machining. The major concern in terms of trustworthiness and durability of SLM parts is its performance under fatigue loading (cyclic loading), which is the most common mode of mechanical failure in engineering structures. Although significant research has been conducted in optimising SLM process parameters, changes in building direction (BD) and laser power (P) can cause variation in microstructure which consequently affecting its mechanical properties. BD orientations of an SLM part significantly affect its columnar grain structure, while P settings influence the shape/size of its meltpool boundary. Currently, there is a lack of research reported on the Fatigue Crack Growth Rate (FCGR) behaviour of SLM superalloys. FCGR studies provide a relationship between stress intensity factor (ΔK) and crack growth rate (da/dN), which can be used to predict the life of a structure that experiences cyclic loading. Most available literatures focus on discovering the differences between the FCGR parameters (FCGR threshold: ΔKth and Paris constants: C and, m) for samples with different BD orientations, or between SLM build samples and traditionally build samples. Literature has not critically investigated the crack growth pathway in SLM’s columnar grain structure, which influences the FCGR resistance, thus affecting the FCGR parameters. Since there is no FCGR experiment reported for SLM Co-Cr-Mo and Inconel 738 superalloys, these two materials will be used to fill the research gap. Therefore, by conducting FCGR experiment, which allows the monitoring of a controlled crack movement, the aim of this PhD research aims…
abstract: The production of cobalt-based and nickel-based superalloys via Selective Laser Melting (SLM) has been successfully applied in low-mass production, particularly in producing components/equipment for the spacecraft and medical industries. SLM technique allows complex and customised parts to be produced rapidly, replacing the traditional process of investment casting and machining. The major concern in terms of trustworthiness and durability of SLM parts is its performance under fatigue loading (cyclic loading), which is the most common mode of mechanical failure in engineering structures. Although significant research has been conducted in optimising SLM process parameters, changes in building direction (BD) and laser power (P) can cause variation in microstructure which consequently affecting its mechanical properties. BD orientations of an SLM part significantly affect its columnar grain structure, while P settings influence the shape/size of its meltpool boundary. Currently, there is a lack of research reported on the Fatigue Crack Growth Rate (FCGR) behaviour of SLM superalloys. FCGR studies provide a relationship between stress intensity factor (ΔK) and crack growth rate (da/dN), which can be used to predict the life of a structure that experiences cyclic loading. Most available literatures focus on discovering the differences between the FCGR parameters (FCGR threshold: ΔKth and Paris constants: C and, m) for samples with different BD orientations, or between SLM build samples and traditionally build samples. Literature has not critically investigated the crack growth pathway in SLM’s columnar grain structure, which influences the FCGR resistance, thus affecting the FCGR parameters. Since there is no FCGR experiment reported for SLM Co-Cr-Mo and Inconel 738 superalloys, these two materials will be used to fill the research gap. Therefore, by conducting FCGR experiment, which allows the monitoring of a controlled crack movement, the aim of this PhD research aims…
author: Anuar, Amir
keywords: Additive manufacturing, Fatigue crack growth, Supperalloys, Selective laser melting
date published: 2021
date modified: 2026-07-27T18:46:13Z
provider: AUT University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: AUT University