Gennari Claudio, Pezzato Luca, Tarabotti Gianmarco, Zambon Andrea, Di Schino Andrea, Calliari Irene
Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padua, Italy.
Department of Management and Engineering, University of Padua, Stradella S. Nicola 3, 36100 Vicenza, Italy.
Materials (Basel). 2020 Apr 1;13(7):1613. doi: 10.3390/ma13071613.
Prestrained at 5% and 15% duplex stainless steel UNS S32750 specimens have been subjected to electropulsing treatments with current density of 100 A/mm and 200 A/mm and 100 and 500 pulses for each current density value. Corrosion tests, X-ray diffraction, microhardness and residual stresses were collected before and after the electropulsing treatments. Tensile tests were performed after the electropulsing treatments in order to compare the mechanical response to reference tensile tests performed before pulsing treatments. Increase in fracture strain was observed after pulsing treatment in comparison to the reference tensile tests. A decrease in microhardness was also observed after electropulsing treatments for both degrees of prestrain. Electropulsing treatment almost eliminates the work-hardened state in the 5% prestrained specimens while partially recovered the 15% prestrained material increasing both uniform and fracture strain. Bulk temperature of the samples remained the same for all treatments duration. The effect are to be addressed to a combined effect of increase in atomic flux due to the electrical current and local joule heating in correspondence of crystal defects. Electropulsing treatment applied to metallic alloys is a promising technique to reduce the work hardening state without the need of annealing treatments in a dedicated furnace.
对5%和15%预应变的双相不锈钢UNS S32750试样施加了电脉冲处理，电流密度分别为100 A/mm和200 A/mm，每个电流密度值分别施加100和500个脉冲。在电脉冲处理前后进行了腐蚀试验、X射线衍射、显微硬度和残余应力测试。在电脉冲处理后进行拉伸试验，以便将力学响应与脉冲处理前进行的参考拉伸试验进行比较。与参考拉伸试验相比，脉冲处理后观察到断裂应变增加。对于两种预应变程度，电脉冲处理后也观察到显微硬度降低。电脉冲处理几乎消除了5%预应变试样中的加工硬化状态，同时部分恢复了15%预应变材料，增加了均匀应变和断裂应变。在所有处理持续时间内，样品的整体温度保持不变。这些效果归因于电流引起的原子通量增加和晶体缺陷处的局部焦耳热的综合作用。对金属合金施加电脉冲处理是一种很有前途的技术，无需在专用炉中进行退火处理即可降低加工硬化状态。
