Nataliya Perevoshchikova, Jordan Rigaud, Yu Sha, Martin Heilmaier, Barrie Finnin, Elena Labelle and Xinhua Wu
The Ni-based superalloy IN-738 LC is known to be susceptible to porosity and different types of cracking during the build-up process and, thus, challenging to manufacture using…
Abstract
Purpose
The Ni-based superalloy IN-738 LC is known to be susceptible to porosity and different types of cracking during the build-up process and, thus, challenging to manufacture using selective laser melting (SLM). Determining a feasible set of operating parameters for SLM of nickel-based superalloys involves new approach to experimental design based on the Doehlert method that assists in determining an optimal (feasible) set of operating parameters for SLM of IN-738 LC powder alloy.
Design/methodology/approach
The SLM parameters are evaluated in terms of their effectiveness in obtaining the microstructure with a porosity content of <0.5 per cent and without micro-cracking. The experimental approach is exemplified with the Doehlert matrix response variable, relative density, by comparing Archimedes method with microstructural assessments of pores and cracks from image analysis. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure of the SLMed IN-738 LC powder alloy has been examined and the consequential tensile response characterised.
Findings
By using optimised process parameters (low heat input, medium scanning speed and small hatching distance) which provides medium energy density, samples of IN-738 LC with a macroscopic porosity <0.5 per cent and free of micro-cracks can be manufactured by SLM. The results indicate that HIP of SLMed material did not lead to a noticeable effect on mechanical properties compared to HT of SLMed material suggesting that the level of both porosity and crack density might be already below the detection limit for the mere heat-treated material.
Originality/value
SLM processing parameters (power, scan speed, hatching distance) for IN-738 LC were successfully optimised after only 14 experiments using Doehlert design. Two independent methods, Archimedes method and image analysis, were used in this study to assess relative density of SLM-produced samples with sets of processing parameters showing coherency in prediction with predicted response by Doehlert design.
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Syahnur Farhana Haji Shahlehi, Vivi Nabilah Shaya, Kamariah Ismail and Farahiyah Kawi
Despite the world’s effort in grappling with the coronavirus disease that has affected many sectors globally, knowledge and research on the COVID-19 pandemic as well as on the…
Abstract
Purpose
Despite the world’s effort in grappling with the coronavirus disease that has affected many sectors globally, knowledge and research on the COVID-19 pandemic as well as on the halal food and beverage industry remain limited, particularly in Brunei Darussalam. Hence, the purpose of this paper is to investigate the challenges that small- and medium-sized enterprises (SMEs) in the halal food processing industry face amid the COVID-19 pandemic in the sultanate.
Design/methodology/approach
A qualitative approach based on four semi-structured interviews was employed using a purposive sampling of managers and business owners of the manufacturing SMEs. Several government agencies were also interviewed to further supplement the findings. This paper also uses the support from a review of relevant academic journal articles, and other secondary data including newspapers and websites, to uncover the hindering factors surrounding the phenomenon.
Findings
Four themes emerged, covering four overarching and inter-related challenges including limited production; closure of retail stores; delay in exporting; and less sales to cover overheads.
Research limitations/implications
This study positively contributes to the understanding of the challenges that the COVID-19 pandemic has brought into the country as well as adds and enriches the halal research sphere. Several implications for the SMEs, policymakers, as well as academic scholars, and limitations are also discussed.
Originality/value
To the best of the authors’ knowledge, this study is among the first to investigate the halal food processing industry in Brunei Darussalam especially, during the time of uncertainties such as the COVID-19 era. The paper’s value also lies in addressing the gap that there is a need to study on the impact of this outbreak on SMEs in the developing countries, inclusive of Brunei Darussalam.