| Summary: | This paper discusses the influence of heat treatment condition of aluminum alloy upon cutting mechanism. The orthogonal cutting experiments of A2017-T3 and A2017-O with a cutting speed of from 0.5 m/s to 160 m/s are conducted. The experiments obtain the following results: A2017-T3 forms discontinuous and serrated chip, while A2017-O forms continuous flow-type chip, regardless of cutting speed. The tendencies of the changes in shear angle, cutting forces, friction angle and the shear stress on the shear plane with the cutting speed are the same between A2017-T3 and A2017-O, when the cutting speed is less than 80 m/s. The significant dissimilarities in the cutting mechanism, however, between A2017-T3 and A2017-O come to appear gradually, when the cutting speed exceeds 80 m/s. For A2017-T3, the shear stress on the shear plane is steady, and the friction angle at the tool-chip interface increases slightly in such a high-speed cutting condition. In contrast, for A2017-O, the shear stress on the shear plane rises gradually, while the friction angle keeps decreasing with the cutting speed. An analysis based on the simple shear model shows that the shear strain rate at the shear zone reaches up to 107 1/s when the cutting speed is beyond 80 m/s. The appearance of these dissimilarities in the cutting mechanism due to the difference in the heat treatment conditions will depend on the characteristics of dynamic plastic behavior and dynamic friction property of aluminum alloy appearing at high-strain-rate fields.
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