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Background: To describe the complex mechanical behavior of S32760 duplex stainless steel under high strain rate and high-temperature loading conditions.Objective: The constitutive model of S32760 duplex stainless steel suitable for high strain rate was constructed from the micro-scale.Methods: Based on the theory of dislocation dynamics, the effects of different strain rates and strains on the plastic deformation of ferrite and austenite were analyzed, and the thermal stress term and non-thermal stress term of ferrite and austenite phases were coupled.Results: The simulation results of the model show that the S32760 dual-phase constitutive model has a high degree of fit with the experimental data at high strain rates.Conclusion: Compared with the classical J-C model, the results show that the constitutive model of this patent has more accurate predictability than the J-C model in describing the mechanical behavior of duplex stainless steel in the high strain range of 5000s-1to 10000s-1.

Cutting temperature is playing a key role in evaluating the cutting process, which significantly affects the tool wear and the quality of the workpiece. Aiming at the problems of low precision, low aging, and poor stability of cutting temperature measurement on the front tool face, an integrated design and production scheme of a high sensitivity built-in wireless temperature measurement tool was proposed. The temperature distribution position on the front tool face was analyzed with 3D finite element simulation software, and the thermal contact position of the main and secondary film thermocouples was determined. SiO2insulated films and NiCr/NiSi film thermocouples were prepared on the front tool surface by femtosecond laser micromachining, electrolyte-plasma polishing, plasma enhanced chemical vapor deposition and magnetron sputtering, and a static calibration experiment system for sensitivity and accuracy of the temperature measuring tool for the film thermocouple was established, and Seebeck coefficient of the film thermocouple was obtained. According to the actual cutting conditions, the wireless temperature measuring system of the thin film thermocouple tool was built and the field cutting test was carried out to obtain the influence law of different cutting parameters on the cutting temperature, and further verify the feasibility of the thin film temperature measuring sensor. The research results show that: Seebeck coefficients of the two kinds of thermocouples prepared by the NiCr/NiSi thin film thermocouple temperature measuring tool are 34.97 μV/°C and 34.96 μV/°C, and the slope of the temperature data fitting curve is 1.00398 and 0.997475, respectively. The linear correlation coefficient R2is close to 1, which is close to the standard K-type thermocouple, which shows good sensitivity and accuracy. At the same time, the temperature measurement results are close to the commercial standard K thermocouple, and the error is less than 5%, indicating that the developed film thermocouple has a high measurement accuracy and can meet the needs of temperature measurement. Actual cutting test is carried out with developed wireless temperature measuring device of thin film thermocouple, which shows this device can meet the requirements of tool temperature measurement, and the feasibility of thin film temperature measuring sensor is further verified. The research provide technical reference for industrial intelligent manufacturing in order to realize the wireless measurement of cutting area temperature of tool front.