Paul Santanu, Singh Ramesh, Yan Wenyi, Samajdar Indradev, Paradowska Anna, Thool Khushahal, Reid Mark
Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC, 3800, Australia.
Sci Rep. 2018 Oct 3;8(1):14726. doi: 10.1038/s41598-018-32842-z.
Laser material deposition based restoration of high-value components can be a revolutionary technology in remanufacturing. The deposition process induces residual stresses due to thermomechanical behavior and metallurgical transformations. The presence of tensile residual stresses in the deposited layer will compromise the fatigue life of the restored component. We have developed a novel fully coupled metallurgical, thermal and mechanical (metallo-thermomechanical) model to predict residual stresses and identified a critical deposition height, which ensures compressive residual stresses in the deposited layer. Any lower deposition height will result in tensile residual stresses and higher deposition height will result in excessive dilution (substrate melting). We have validated the model using neutron and micro-focus X-ray diffraction measurements. This study highlights that the critical deposition height corresponds to the minimum cooling rate during solidification. It addresses one of the major outstanding problems of additive manufacturing and paves a way for "science-enabled-technology" solutions for sustainable restoration/remanufacturing.
基于激光材料沉积的高价值部件修复技术可能成为再制造领域的一项革命性技术。由于热机械行为和冶金转变，沉积过程会产生残余应力。沉积层中拉伸残余应力的存在会损害修复部件的疲劳寿命。我们开发了一种新颖的完全耦合的冶金、热和机械（金属热机械）模型来预测残余应力，并确定了一个临界沉积高度，该高度可确保沉积层中存在压缩残余应力。任何低于临界沉积高度都会导致拉伸残余应力，而高于临界沉积高度则会导致过度稀释（基体熔化）。我们使用中子和微焦点X射线衍射测量对该模型进行了验证。这项研究表明，临界沉积高度对应于凝固过程中的最小冷却速率。它解决了增材制造的一个主要突出问题，并为可持续修复/再制造的“科学驱动技术”解决方案铺平了道路。
