Understanding processing parameters affecting residual stress in selective laser melting of Inconel 718 through numerica
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Understanding processing parameters affecting residual stress in selective laser melting of Inconel 718 through numerical modeling Jia Song1 , Liang Zhang1,a) , Wenheng Wu1,b), Beibei He1, Xiaoqing Ni1, Jiongkai Xu1, Guoliang Zhu2, Qiyun Yang1, Tao Wang1, Lin Lu1 1
Shanghai Engineering Research Center of 3D Printing Materials, Shanghai Research Institute of Materials, Shanghai 200437, China Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China a) Address all correspondence to these authors. e-mail: [email protected] b) e-mail: [email protected] 2
Received: 8 October 2018; accepted: 24 December 2018
In this study, a thermal–elastic–plastic finite element model is proposed to investigate the effect of volume energy density on the temperature field, molten pool size, and residual stress distribution in the selective laser melting (SLM) process of Inconel 718 alloy. A temperature-dependent thermal–mechanical property of materials is considered, as well as the properties conversion between powder layer and solidified alloy. Within the scope of the study parameters, the simulated molten pool size increases with increasing volume energy density and exhibits linear growth relationship, which are validated by the experimental results and show a good agreement. In addition, five scanning strategies are adopted to study the effect of these scanning strategies on the residual stress distribution in this research. The results show that the residual stress distribution of SLM Inconel 718 specimen largely depends on the scanning strategy. Finally, to reveal the mechanism of residual stress formation, the restraint bar model is used to further analyze the formation mechanism of residual stress during the SLM process.
Introduction Nickel-based Inconel 718 superalloy is a Ni–Fe–Cr austenite alloy, which has several good performances, especially in hightemperature working conditions. It is an essential material for manufacturing gas turbine blades, combustors, turbo charger rotors, and a variety of corrosion containments and structural applications up to 700 °C [1, 2, 3, 4]. In recent years, many new designs of high-complex Inconel 718 components made by additive manufacturing (AM) provide an improvement in their performances. Differ from traditional subtractive manufacturing, the AM allows the design of the components more complex and more flexibility, such as integration design, internal flow path, grillage structure, etc. Selective laser melting (SLM), as one of major AM technologies, supplies a promising perspective for designing and production of high-complex components with near net
ª Materials Research Society 2019
shape and has attracted more and more attention in aerospace and aviation industries [5, 6]. However, there are several challenges in SLM process which limit its further application and development, such as porosity, microcracks, thermal stress, residual stress, distortion, dimensi
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