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Indexed by:期刊论文

Date of Publication:2011-06-01

Journal:ADVANCED SCIENCE LETTERS

Included Journals:Scopus、SCIE

Volume:4

Issue:6-7

Page Number:2493-2497

ISSN No.:1936-6612

Key Words:High Speed Machining; Serrated Chip; Adiabatic Shear Band; Fracture; Microstructure

Abstract:The microstructure of the adiabatic shear bands and the microscopic pattern of the adiabatic shear fracture surfaces within the serrated chips formed by high speed cutting of hardened steel AISI 1045 were observed and analyzed by using optical microscope, SEM and TEM. The results show that the deformed band is a deformation microstructure elongated along shear direction and a large number of very fine non-deformed structure distribute in the center of transformed band. In addition, the striate structures distribute along the shear direction on the adiabatic shear fracture surfaces within the serrated chips with deformed bands, while a large number of elongated along the shear direction and parabolic shape dimples cover the fracture surface of transformed bands. This study indicates that adiabatic shear fracture occurred in primary shear zone during formation of serrated chip with deformed bands is a dynamic brittle damage fracture due to micro-crack accumulation, while adiabatic shear fracture of serrated chip with transformed bands is proceeding in the mode of dynamic ductile damage fracture caused by microvoid nucleation, growth and coalescence.