Bandyopadhyay Amit, Upadhyayula Mahadev, Traxel Kellen D, Onuike Bonny
W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA.
Mater Lett. 2019 Nov 15;255. doi: 10.1016/j.matlet.2019.126541. Epub 2019 Aug 16.
Understanding processing-property relationships for directed-energy-deposition (DED) parts remains a major roadblock to widespread process implementation. Herein we investigate the effect of scanning-strategy and testing-orientation on the fatigue response of as-printed Ti6Al4V components. At ~10 cycles, samples tested in the build-direction exhibited ~ 45% decrease in fatigue strength relative to the horizontally-tested samples, owing to higher overall porosity and the testing orientation relative to residual pores. Samples failing <10 cycles demonstrated tortuous surfaces, whereas samples enduring >10 cycles exhibited smoother-surfaces. Our results indicate that DED-produced parts can exhibit directionally-dependent fatigue performance, and print-strategy must be taken into consideration for dynamic-loading applications.
理解定向能量沉积（DED）部件的加工-性能关系仍然是该工艺广泛应用的主要障碍。在此，我们研究了扫描策略和测试方向对增材制造Ti6Al4V部件疲劳响应的影响。在约10次循环时，沿构建方向测试的样品相对于水平测试的样品疲劳强度降低了约45%，这是由于总体孔隙率较高以及相对于残余孔隙的测试方向所致。循环次数小于10次时失效的样品表面呈曲折状，而经受超过10次循环的样品表面则较为光滑。我们的结果表明，DED制造的部件可能表现出方向依赖性疲劳性能，对于动态加载应用，必须考虑打印策略。
