SLM增材制造Ti-6Al-4V合金试样的孔隙缺陷疲劳分析

Fatigue Analysis of Pore Defects in Ti-6Al-4V Alloy by Selective Laser Melting

以Ti-6Al-4V合金为对象,基于ABAQUS和FE-SAFE,建立了增材制造过程中孔隙形状、位置、大小、相互距离、数量及孔隙率等模型,研究了孔隙对SLM增材制造Ti-6Al-4V合金试样疲劳寿命的影响。结果表明,球形孔比椭球形孔对疲劳寿命影响更小。在孔隙半径为10~30μm时,球形内部孔隙缺陷比表面孔隙缺陷对疲劳寿命影响更显著;在孔隙半径为40~70μm时,表面孔隙缺陷比内部孔隙缺陷对疲劳寿命影响更大。孔隙率低于1%时,球形孔隙缺陷半径越大的试样疲劳寿命变化幅度越大;孔隙率处于1%~5%之间时,混合孔隙缺陷的试样疲劳寿命最短。疲劳寿命会随着不同随机排列方式在一定范围内波动。

Taking Ti-6Al-4V alloy as object,the model for shape,location,size,mutual distance,number and porosity of pore defects during additive manufacturing process was established by ABAQUS and FE-SAFE,and effects of pore defects on the fatigue life of SLMed Ti-6Al-4V alloy specimens were investigated.The results indicate that the influence of spherical pores on fatigue life is lower than non-spherical pores.In range of 10~30μm,influence of spherical internal pore defects on fatigue life is more significant.In range of 40~70μm,influence of surface pore defects on fatigue life is more obvious than internal pore defects.The rangeability in fatigue life of specimen is increased with increase in radius of spherical pore defect when the porosity is less than 1%.The fatigue life of specimens with mixed pore defects reaches the minimum value with porosity of 1%~5%.The fatigue life fluctuates in a range with different random arrangements.