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对真空冶炼铸造Ti-6Al-4V钛合金(简称ZTC4)表面α污染层的组织、氧氢含量及纳米硬度趋势进行了研究,分析了α污染层对铸造钛合金拉伸性能的影响。结果表明,α污染层为粗大的片状结构,最大深度为0.28 mm;与心部区域相比,氧元素含量增加了1.64倍,氢元素减少了1倍,0硬度值增加了0.94倍,α污染层对ZTC4的拉伸性能影响显著,与不含α污染层试样相比,屈服强度、抗拉强度、延伸率和断面收缩分别降低了14.2%、12.5%、20%和35%,这是由于氧等原子固溶在试样表面形成脆而硬的α污染层,在拉伸载荷作用下α层不易变形形成多源断裂,在材料最薄弱区域形成宏观断裂源并向基体快速扩展,最后形成脆性解理断裂。
The microstructure, oxygen and hydrogen content and nanohardness of the α-polluted layer on the vacuum smelting Ti-6Al-4V titanium alloy (referred to as ZTC4) were studied, and the influence of α-polluted layer on the tensile properties of the cast titanium alloy was analyzed. The results show that the α-polluted layer is a coarse sheet-like structure with the maximum depth of 0.28 mm. Compared with the heart region, the content of oxygen increases by 1.64 times, the hydrogen decreases by 1 times and the hardness increases by 0.94 times, α The contamination layer has a significant effect on the tensile properties of ZTC4, which is 14.2%, 12.5%, 20% and 35% lower than that of the α-contaminated layer, respectively Due to the solid solution of oxygen and other atoms on the surface of the sample to form a brittle and hard α-polluted layer. Under tensile load, the α-layer is not easily deformed to form multi-source faults, and macroscopic fracture sources are formed in the weakest area of the material and rapidly expand to the matrix. Finally, the formation of brittle cleavage fracture.