研究了第二相对Ti 2 5V 15Cr 2Al 0 .2C x (x=0 ,2 %Mo,2 %Nb ,0 .2 %Si)阻燃β钛合金拉伸断裂行为的影响。结果表明 ,β晶界上析出的α相增加了合金发生沿晶断裂的趋势 ,特别是热暴露后形成的连续晶界α膜是导致合金脆性沿晶断裂的主要原因。虽然粗大的碳化物颗粒是合金中的裂纹源之一 ,但细小、弥散分布的碳化物却能显著降低合金发生脆性沿晶断裂的趋势 ,其原因是细化了β晶粒和有效抑制了晶界α沉淀的析出 The effect of the second phase on the tensile fracture behavior of the flame-retarded β-Ti alloy with Ti 2 V 5 15Cr 2Al 0 .2C x (x = 0, 2% Mo, 2% Nb, 0.2% Si) The results show that the α phase precipitated on the β grain boundary increases the tendency of intergranular fracture, and the continuous grain boundary α film formed after thermal exposure is the main reason for the brittle intergranular fracture. Although coarse carbide particles are one of the crack sources in the alloy, fine and dispersed carbides can significantly reduce the tendency of brittle fracture along the crystal, which is due to refining the β grains and effectively inhibiting the crystallization Boundary precipitation α precipitation