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研究了样品尺寸对电子束逐层熔化成形Ti-6Al-4V合金组织和力学性能的影响。结果表明:EBM法制备Ti-6Al-4V合金组织为α+β相。随着样品尺寸的减小,α片层厚度减小,位错密度增加,导致其强度升高,塑性下降。这一变化趋势在直径小于4 mm时比较明显,当样品直径大于4 mm后,强度随尺寸增加缓慢增加,塑性基本保持不变。样品沿垂直于基板方向生长时,会存在由细小针状α?马氏体相组成的不稳定生长区.随着距基板距离的增加,逐渐稳定生长。该不稳定生长区随着样品直径的增大逐渐减少。
The effect of sample size on the microstructure and mechanical properties of Ti-6Al-4V alloy by electron beammelting was investigated. The results show that the microstructure of Ti-6Al-4V alloy prepared by EBM is α + β phase. As the sample size decreases, the thickness of the α sheet decreases and the dislocation density increases, resulting in an increase in strength and a decrease in ductility. The trend of this trend is obvious when the diameter is less than 4 mm. When the diameter of the sample is more than 4 mm, the strength increases slowly with the increase of size, and the plasticity remains basically unchanged. When the sample grows perpendicular to the substrate, there will be an unstable growth zone composed of fine needle-like α-martensite phase, and gradually grows steadily as the distance from the substrate increases. The unstable growth zone decreases with increasing sample diameter.