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针对TC4钛合金氩弧直、斜焊缝的疲劳性能展开对比研究,对氩弧直、斜焊缝的微观组织和疲劳性能进行了对比测试与分析。结果表明:TC4钛合金氩弧焊焊缝显微组织原始β相不断长大,与母材区相比晶粒更粗大;斜焊缝试件的中值疲劳寿命是直焊缝的1.4倍;直、斜焊缝试件疲劳裂纹均起始于试件内部气孔缺陷处,直焊缝试件裂纹在焊缝区扩展至断裂,扩展区有脆性解理特征,而斜焊缝试样裂纹穿过焊缝进入母材扩展至断裂,扩展区有典型韧性扩展特征;在瞬断区,斜焊缝试件比直焊缝表现出更好的韧性。
Aiming at the fatigue performance of the straight and oblique weld of TC4 titanium alloy, the contrastive study was conducted and the microstructure and fatigue properties of straight and oblique weld seam were tested and analyzed. The results show that the original β phase of microstructure of TC4 titanium alloy weld continuously grows larger than that of base metal. The median fatigue life of oblique weld is 1.4 times that of straight weld. The fatigue cracks of straight and incline welded specimens all start from the internal porosity defects in the specimens. The cracks in the straight welded specimens extend to the fracture in the weld zone and the brittle cleavage features in the extended zone, while the cracks in the oblique weld The weld passes into the base metal and expands to fracture, and the extension zone has typical ductile expansion characteristics. In the transient zone, the incline weld shows better toughness than the straight weld.