부산대학교 도서관

Microstructural change in 93W-4.9Ni-2.1Fe heavy alloy was investigated by metallurgical analyses of the fragments from penetrators after high speed impact test. Two kinds of specimens were prepared. The one was normal specimen manufactured by a typical liquid phase sintering process, and the other was the D specimen made by a double-cycle sintering process, respectively. The morphology of tungsten grain in the D specimen became irregular by the double-cycle sintering. And microstructural changes observed from the fragments after the test were local deformation in W grain and matrix phase, fracture, formation of adiabatic shear band, reaction with steel target and so on, irrespective of the specimens. However, fracture mode was changed from W-W and W-matrix interface to W cleavage when W grains became irregular, by which the penetrator could be more brittle and fragile. From the analyses, it was suggested that the microstructural change in tungsten grain and formation of inhomogeneous matrix band would be beneficial for the self sharpening effect.