Abstract An important advantage of AM is to create net-shaped components with no need for further surface machining since it is usually very difficult for complex geometries. The effect of surface roughness on fatigue performance of powder bed fusion additively manufactured metals was evaluated in this work. The intrinsic rough surface of metal AM parts that could act like existing surface cracks and significantly affect fatigue performance is investigated. The effect of processing and post-processing conditions on surface roughness of AM parts are reviewed and the effect of surface roughness on fatigue performance is analyzed. The synergistic effect of internal defects and surface roughness on fatigue performance is also evaluated. Arithmetic mean surface roughness parameter Ra is used here as a representation of surface roughness, since this parameter has been presented in most of the studies dealing with metal AM surface roughness. Surface roughness effect on fatigue performance is shown to be dominant even in the presence of relatively large internal defects and various microstructures. Ra decreases with an increase in power. This consequently increases fatigue limit, although scatter is observed due to the secondary effect of internal defects and microstructure. For similar microstructures, considering synergistic effect of Ra along with average critical internal defect size in combination with the stress amplitude, resulted in improved correlation of the S-N fatigue data.

中文翻译：

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表面粗糙度对粉末床熔融添加剂制造金属疲劳性能影响的分析

摘要 AM 的一个重要优势是无需进一步表面加工即可创建网状部件，因为通常很难处理复杂的几何形状。在这项工作中评估了表面粗糙度对粉末床熔融增材制造金属疲劳性能的影响。研究了金属增材制造零件的内在粗糙表面，其作用类似于现有的表面裂纹，并显着影响疲劳性能。回顾了加工和后加工条件对增材制造零件表面粗糙度的影响，分析了表面粗糙度对疲劳性能的影响。还评估了内部缺陷和表面粗糙度对疲劳性能的协同作用。这里使用算术平均表面粗糙度参数 Ra 作为表面粗糙度的表示，因为这个参数已经出现在大多数处理金属增材制造表面粗糙度的研究中。即使存在相对较大的内部缺陷和各种微观结构，表面粗糙度对疲劳性能的影响也占主导地位。Ra随着功率的增加而降低。这因此增加了疲劳极限，尽管由于内部缺陷和微观结构的二次影响而观察到分散。对于类似的微观结构，考虑 Ra 与平均临界内部缺陷尺寸以及应力幅度的协同效应，可以提高 SN 疲劳数据的相关性。即使存在相对较大的内部缺陷和各种微观结构，表面粗糙度对疲劳性能的影响仍占主导地位。Ra随着功率的增加而降低。这因此增加了疲劳极限，尽管由于内部缺陷和微观结构的二次影响而观察到分散。对于类似的微观结构，考虑 Ra 与平均临界内部缺陷尺寸以及应力幅度的协同效应，可以提高 SN 疲劳数据的相关性。即使存在相对较大的内部缺陷和各种微观结构，表面粗糙度对疲劳性能的影响也占主导地位。Ra随着功率的增加而降低。这因此增加了疲劳极限，尽管由于内部缺陷和微观结构的二次效应而观察到分散。对于类似的微观结构，考虑 Ra 与平均临界内部缺陷尺寸以及应力幅度的协同效应，可以提高 SN 疲劳数据的相关性。