A New Quantitative Sensitivity Analysis of the Flow Stress of 18 Engineering Materials in Machining

It has long been argued about which effect, among the effects of strain hardening, strain-rate hardening, and temperature softening, is predominant in governing the material flow stress in machining. This paper presents a new quantitative sensitivity analysis of the flow stress of 18 engineering materials based on the well-known Johnson-Cook model. It is demonstrated that the first predominant factor governing the material flow stress is either strain hardening or thermal softening, depending on the specific material employed and the varying range of temperatures. Strain-rate hardening is the least important factor governing the material flow stress, especially when machining aluminum alloys.