离心喷射沉积Ti-48Al-2Mn-2Nb的断裂韧度

Fracture Toughness of Ti-48Al-2Mn-2Nb Produced by Centrifugal Spray Deposition

着重研究了采用真空离心喷射沉积成形的Ti48Al2Mn2Nb金属间化合物及经热等静压处理的合金样品的室温断裂韧度。采用三点弯曲试验方法进行测试,结果表明,喷射沉积合金样品的平均断裂韧度值为236MPam12,最大值约28MPam12,而经热等静压后样品的平均断裂韧度仅为153MPam12。结果分析认为,层片状组织对裂纹扩展的抗力比γ等轴晶的抗力高得多,因而,具有层片状组织的离心喷射沉积合金样品显示了比具有γ等轴晶加层片组织的热等静压样品更高的室温断裂韧度。

The fracture toughness of Ti 48Al 2Mn 2Nb produced by centrifugal spray deposition (CSD) under a low pressure vacuum condition and treated by hot isostatic pressing (HIP) at 1 250℃ has been investigated at ambient temperature using the three point bending test. The results show that the mean value of fracture toughness is approximately 23 6 MPa m 12 and the maximum of fracture toughness reaches 28 MPa m 12 for the CSD sample, while only 15 3 MPa m 12 for the HIP sample. The CSD sample has a finer lamellar structure, but the microstructure of the HIP sample is a duplex structure of lamellar and equiaxed gamma grains, for which reason the much better fracture toughness the sample. The lamellar structure also has better resistance to crack growth than equiaked gamma grains.