The fatigue tests at 200 °C and 400 °C were conducted to investigate the elevated-temperature fatigue behavior of additively manufactured (AM) Ti-6Al-4V alloy with hot isostatic pressing (HIP) treatment. Since the manufacturing defects (i.e., pores) were significantly reduced by HIP treatment, no specimen failed from the pores. Consequently, the present AM Ti-6Al-4V alloy behaved superior to that without HIP treatment. Moreover, the specimens exhibited different failure mechanisms at 200 °C and 400 °C. Fatigue crack initiation at 200 °C mainly was due to surface deformation and strain localization, while the cause became fracture of surface oxygen-rich layer at 400 °C.

中文翻译：

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采用 HIP 处理的增材制造 Ti-6Al-4V 合金在高温下的高周疲劳行为

在 200 °C 和 400 °C 下进行疲劳试验，研究热等静压 (HIP) 处理的增材制造 (AM) Ti-6Al-4V 合金的高温疲劳行为。由于 HIP 处理显着减少了制造缺陷（即气孔），因此没有样品因气孔而失效。因此，本发明的 AM Ti-6Al-4V 合金的性能优于未经 HIP 处理的合金。此外，样品在 200 °C 和 400 °C 下表现出不同的失效机制。 200 ℃时疲劳裂纹的萌生主要是由于表面变形和应变局部化，而400 ℃时则是表面富氧层断裂。