Study on High Quality Machining of Hard and Brittle Materials : 1st Report, Deformation and Fracture Behavior at Low Temperature

Abstract

The results of basic experimental study on cryogenic machining of hard and brittle materials are presented in this paper. In order to understand the basic phenomenon of material deformation and fractue during machining the hard and brittle materials such as a glass and a semiconductor at low temperature, the indentation tests and single point diamond scratching tests have been carried out. The results of tests showed that the crack length and the indentation depth decreases, the hardness and the critical depth of brittle ductile transition increases with the decrease of material temperature for both soda lime glass and single crystal silicon. The optical microscope observations showed that the deformation behavior and cracking patterns at low temperature are different from those at room temperature. From our experiments, we can conclude that the cryogenic machining is advantageous to restrain generation and propagation of cracks during machining the hard and brittle materials.