| Title |
Adiabatic Shear Band in an HY - 100 steel (3) ( Microstructure ) |
| Authors |
이성학(Sung Hak Lee); 이창길(Chang Gil Lee); 정윤일(Yoon Il Chung); 조경목(Kyung Mox Cho) |
| Abstract |
This paper is concerned with a study of the microstructural development of the adiabatic shear band formed by dynamic torsional experiments using thin-walled tubular specimens of a tempered martensitic HY-100 steel. The strain rates imposed were about 10³/sec and local temperature increases of about 600℃ within the shear bands were measured. The shear band microstructure was examined by optical and transmission electron microscopy, revealing following two distinct microstructures, i.e., highly elongated narrow subgrains extended in the shear direction and fine equiaxed cells. Although the proportions of the two microstructures varied for different specimens, the microstructural observations were interpreted by a process of dynamic recovery accompanying large deformation and high temperature rise within the shear band. There was no evidence to support phase transformation to austenite followed by martensite formation or dynamic recrystallization. |