Inconel 625 specimens with different levels of purposely induced defects (up to ~3% of specimen volume) were manufactured by laser powder bed fusion. They were subjected to a stress relief annealing followed by hot isostatic pressing. After each step of post-processing, the residual porosity and the pore size distribution were measured using the computed tomography technique. Tensile and fatigue crack growth testing were then carried out to evaluate the impact of residual defects on the mechanical resistance and damage tolerance of the manufactured specimens. Hot isostatic pressing was effective in reducing the processing-induced defect count and size, but near-the-surface defects were still observed. Large clusters of residual defects were also observed for specimens manufactured with ~3% porosity. The elongation at break, and, to a lesser extent, the tensile strength were impacted by an as-manufactured porosity as small as 0.25%. Fatigue crack growth testing showed that HIP increases the threshold stress intensity factor for long fatigue crack propagation from ~7 to ~9 MPa*m^1/2 and that irrespective of the level of as-manufactured porosity. An as-manufactured porosity smaller that 1% did not impact the fatigue crack growth rate of hot isostatic pressed specimens significantly, whereas occasional crack retardation was observed for specimens with an as-manufactured porosity of ~3%.

Inconel 625 试样具有不同程度的故意诱导缺陷（高达试样体积的 3%）通过激光粉末床熔合制造。对它们进行去应力退火，然后进行热等静压。在每个后处理步骤之后，使用计算机断层扫描技术测量残余孔隙率和孔径分布。然后进行拉伸和疲劳裂纹扩展测试，以评估残余缺陷对制造试样的机械阻力和损伤容限的影响。热等静压可有效减少加工引起的缺陷数量和尺寸，但仍观察到表面附近的缺陷。对于孔隙率约为 3% 的样品，也观察到了大量残余缺陷。断裂伸长率，在较小程度上，拉伸强度受到制造时孔隙率的影响，该孔隙率小至 0.25%。疲劳裂纹扩展测试表明，HIP 将长疲劳裂纹扩展的阈值应力强度因子从 ~7 增加到 ~9 MPa*m^1/2并且与制造的孔隙率水平无关。制造时孔隙率小于 1% 不会显着影响热等静压试样的疲劳裂纹扩展速率，而制造时孔隙率约为 3% 的试样偶尔会出现裂纹延迟。