TC18合金的显微组织及断裂韧性

Microstructure and fracture toughness of TC18 alloy

测试了TC18合金国产锻件的断裂韧性,观察了其显微组织及断口形貌,并将其与TC18合金进口锻件的断裂韧性进行了对比。结果表明:TC18合金国产锻件L(纵向)、T(横向)向均为网篮状组织,且无明显差异、分布较均匀;国产锻件L向的断裂韧度KIC平均值较T向高7.4 MPa·m^(1/2),分布较集中;与进口锻件相比,国产锻件L、T向的断裂韧度平均值均较高,这主要与其具有不同的组织形貌有关:网篮状组织抵抗裂纹扩展的能力要优于等轴状组织,因而具有网篮状组织的国产锻件的断裂韧度要优于具有等轴状组织的进口锻件。

Fracture toughness of the TC18 alloy domestic forgings was tested, and then the microstructure as well as fracture morphology were observed. Moreover, the fracture toughness of the domestic forgings compared with that of the imported forgings. The results show that the microstructure of both the longitudinal and transverse direction of the domestic forgings are basketweave microstructure like and are distributed homogeneously along all the directions. The average value of the fracture toughness Kicin the longitudinal direction of the domestic forgings is about 7.4 MPa ~ m~/2 higher than that in the transverse direction and there is no obvious difference in the value of K^c. Compared with the imported forgings, whatever the direction is, the average fracture toughness K^c of the domestic forgings is higher than that of the imported forgings, which should be related to the microstructure difference： the domestic forgings are with basketweave and its ability to resist crack propagation is stronger than that of the imported forgings with equiaxed microstructure.