The biggest critique of metal 3D printing is that the finished product is just not strong enough. Well, researchers from Sweden, the UK, and China have found a way to add strength and ductility to metal 3D Printing.
….thanks to a team of researchers from Stockholm University in Sweden, the University of Birminghamin the UK, and China’s Zhejiang University, a new metal 3D printing technique can be used to manufacture metals that have both excellent ductility and strength, compared to metal parts made using more traditional manufacturing methods.
“Strength and ductility are natural enemies of one another, most methods developed to strengthen metals consequently reduce ductility,” explained Dr. Leifeng Liu, the project head and an AMCASH research fellow at the University of Birmingham. “The 3D printing technique is known to produce objects with previously inaccessible shapes, and our work shows that it also provides the possibility to produce the next generation of structural alloys with significant improvements in both strength and ductility.”
The joint research team recently published the findings on their new SLM method, which involves a popular stainless steel, in a paper, titled “Dislocation network in additive manufactured steel breaks strength-ductility trade-off,” in the Materials Todayjournal; co-authors include Dr. Liu, Qingqing Ding, Yuan Zhong, Ji Zou, Jing Wu, Yu-Lung Chiu, Jixue Li, Ze Zhang, Qian Yu, and Zhijian Shen.
According to the paper’s abstract, “Most mechanisms used for strengthening crystalline materials, e.g. introducing crystalline interfaces, lead to the reduction of ductility. An additive manufacturing process – selective laser melting breaks this trade-off by introducing dislocation network, which produces a stainless steel with both significantly enhanced strength and ductility. Systematic electron microscopy characterization reveals that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal ‘modulator’ that is able to slow down but not entirely block the dislocation motion. It also promotes the formation of a high density of nano-twins during plastic deformation. This finding paves the way for developing high performance metals by tailoring the microstructure through additive manufacturing processes.”
The researchers were able to optimize the process parameters during 3D printing to achieve their results, which could help accelerate the technology toward manufacturing strong and ductile heavy-duty parts.
“This work gives researchers a brand new tool to design new alloy systems with ultra-mechanical properties,” said Dr. Liu. “It also helps metal 3D printing to gain access into the field where high mechanical properties are required like structural parts in aerospace and automotive industry.”
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