采用扫描电子显微镜(scanning electron microscope,SEM)、原子力显微镜(atomic force microscope,AFM)及电化学工作站等仪器,研究退火温度和时间对镍钛合金表面形貌、表面粗糙度以及耐腐蚀性能的影响。从SEM和AFM分析结果可知,在400~60...采用扫描电子显微镜(scanning electron microscope,SEM)、原子力显微镜(atomic force microscope,AFM)及电化学工作站等仪器,研究退火温度和时间对镍钛合金表面形貌、表面粗糙度以及耐腐蚀性能的影响。从SEM和AFM分析结果可知,在400~600℃退火温度内,随着退火温度升高,镍钛合金表面先产生小颗粒,最后这些小颗粒连接形成片状形貌,而表面粗糙度随着温度升高呈现增大趋势。改变退火时间时,表面形貌的变化趋势基本和处理温度相似,表面粗糙度在退火时间15 min时最小。用电化学工作站测试得到极化曲线,表明退火温度400℃和500℃时试样有较好的耐腐蚀性能。短时保温易获得良好的耐腐蚀性能。展开更多
The theoretical model of axial ultrasonic vibration grinding force is built on the basis of a mathematical model of cutting deforming force deduced from the assumptions of thickness of the undeformed debris under Rayl...The theoretical model of axial ultrasonic vibration grinding force is built on the basis of a mathematical model of cutting deforming force deduced from the assumptions of thickness of the undeformed debris under Rayleigh distribution and a mathematical model of friction based on the theoretical analysis of relative sliding velocity of abrasive and workpiece. Then, the coefficients of the ultrasonic vibration grinding force model are calculated through analysis of nonlinear regression of the theoretical model by using MATLAB, and the law of influence of grinding depth, workpiece speed, frequency and amplitude of the mill on the grinding force is summarized after applying the model to analyze the ultrasonic grinding force. The result of the above-mentioned law shows that the grinding force decreases as frequency and amplitude increase, while increases as grinding depth and workpiece speed increase; the maximum relative error of prediction and experimental values of the normal grinding force is 11.47% and its average relative error is 5.41%; the maximum relative error of the tangential grinding force is 10.14% and its average relative error is 4.29%. The result of employing regression equation to predict ultrasonic grinding force approximates to the experimental data, therefore the accuracy and reliability of the model is verified.展开更多
文摘采用扫描电子显微镜(scanning electron microscope,SEM)、原子力显微镜(atomic force microscope,AFM)及电化学工作站等仪器,研究退火温度和时间对镍钛合金表面形貌、表面粗糙度以及耐腐蚀性能的影响。从SEM和AFM分析结果可知,在400~600℃退火温度内,随着退火温度升高,镍钛合金表面先产生小颗粒,最后这些小颗粒连接形成片状形貌,而表面粗糙度随着温度升高呈现增大趋势。改变退火时间时,表面形貌的变化趋势基本和处理温度相似,表面粗糙度在退火时间15 min时最小。用电化学工作站测试得到极化曲线,表明退火温度400℃和500℃时试样有较好的耐腐蚀性能。短时保温易获得良好的耐腐蚀性能。
基金Project(51275530)supported by the National Natural Science Foundation of China
文摘The theoretical model of axial ultrasonic vibration grinding force is built on the basis of a mathematical model of cutting deforming force deduced from the assumptions of thickness of the undeformed debris under Rayleigh distribution and a mathematical model of friction based on the theoretical analysis of relative sliding velocity of abrasive and workpiece. Then, the coefficients of the ultrasonic vibration grinding force model are calculated through analysis of nonlinear regression of the theoretical model by using MATLAB, and the law of influence of grinding depth, workpiece speed, frequency and amplitude of the mill on the grinding force is summarized after applying the model to analyze the ultrasonic grinding force. The result of the above-mentioned law shows that the grinding force decreases as frequency and amplitude increase, while increases as grinding depth and workpiece speed increase; the maximum relative error of prediction and experimental values of the normal grinding force is 11.47% and its average relative error is 5.41%; the maximum relative error of the tangential grinding force is 10.14% and its average relative error is 4.29%. The result of employing regression equation to predict ultrasonic grinding force approximates to the experimental data, therefore the accuracy and reliability of the model is verified.
