温度对球墨铸铁QTRSi4Mo1拉伸性能与循环变形的影响

EFFECTS OF TEMPERATURE ON TENSILE PROPERTIES AND CYCLIC DEFORMATION OF DUCTILE CAST IRON QTRSI4MO1

开展了球墨铸铁QTRSi4Mo1室温到760℃条件下的静载拉伸试验和应变控制低周疲劳试验研究。通过比较不同温度下材料拉伸性能与循环应力应变响应特性,表明球墨铸铁QTRSi4Mo1在300℃~400℃附近存在一定脆性,在500℃以上具有较好的塑性变形能力;在中温(400℃~500℃)条件下材料循环应力应变行为表现为循环硬化,在高温(760℃)条件下表现为循环软化,而在较低温度下则表现出更复杂的应力应变演化,同时利用Ramberg-Osgood方程可准确描述其循环应力应变特性;在较低温度下材料具有non-Masing特性,而在500℃以上则具有Masing特性。

The static tensile tests and the strain-controlled low cycle fatigue tests of ductile iron QTRSi4 Mo1 at the temperatures ranging from room temperature to 760℃were carried out.By comparing the tensile properties and the cyclic stressstrain response characteristics of the material at various temperatures,it is shown that the ductile cast iron QTRSi4 Mo1 exhibits some brittleness near 300℃~400℃,and has better plastic deformation ability above 500℃.It shows cyclic hardening at medium temperatures(400℃~500℃)for the cyclic stress strain responses while cyclic softening occurs at high temperature(760℃).Besides,more complicated cyclic stress strain evolutions take place at lower temperatures.Meanwhile,the Ramberg-Osgood equation can be adopted to accurately describe the cyclic stress-strain characteristics.The material exhibits non-Masing characteristics at lower temperatures while it shows the Masing characteristics above 500℃.