The University of Massachusetts Amherst
University of Massachusetts Amherst

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Mitigating microscale residual stresses in 3D-printed stainless steel

Wen Chen

Principal Investigator Wen Chen of the Mechanical and Industrial Engineering (MIE) Department has been awarded a three-year, $345,470 grant from the National Science Foundation’s (NSF) Division of Materials Research to investigate microscale residual stresses in additively manufactured stainless steel. Chen says that additive manufacturing, also called 3D printing, could be a key technology for the manufacture of stainless-steel engineering components in automotive, aerospace, defense, biomedical, and other industries if certain “disruptive” aspects can be alleviated. See grant on NSF website.

Chen explains that the high-temperature laser beam used for additive manufacturing of metal alloys usually produces highly heterogeneous microstructures that result in large, non-homogenous, residual stresses in 3D-printed materials and serve to disrupt the manufacturing process and hinder the functioning of the material. He says that residual stresses are generally detrimental to the performance of a material or the life of a component, thus limiting the wide adoption of additive manufacturing in engineering applications.

As Chen notes, while the macroscale residual stresses have been widely studied in the field of metal 3D printing, the origin and control of the microscale residual stresses remain largely unexplored.

In response to this problem, according to Chen, “This research aims to understand and control the microscale residual stresses in additively manufactured stainless steel. Due to its excellent combination of mechanical properties, corrosion, and oxidation resistance, stainless steel is a workhorse material used in a wide range of applications such as cars, ships, airplanes, nuclear power plants, medical implants, etc.”

Chen explains that his collaborative NSF research, teaming with Professor Ting Zhu’s group at Georgia Tech, will investigate the effects of 3D-printed microstructures on the resultant microscale residual stresses in stainless steel by integrating microstructural characterization, mechanical testing, and computational modeling.

“Mechanistic insights gained will be applied to guide additive manufacturing, so as to mitigate the microscale residual stresses in 3D-printed stainless steel,” says Chen. “Results from this research will lay a solid foundation for future development of additively manufactured metallic materials with tailored microstructures and outstanding mechanical performance.”

Chen heads the MIE Multiscale Materials and Manufacturing Laboratory at UMass Amherst, and his research revolves around the interface of materials science and advanced manufacturing.

As Chen summarizes his lab’s research, “We are particularly interested in understanding the fundamental microstructure-property-processing relationships in advanced materials and integrating control over materials on multiple length scales (atomic, microstructural, architectural) through materials processing and additive manufacturing (or 3D printing), to eventually arrive at optimized, multi-functional engineering components.”  (July 2020)