【摘要】 形状记忆合金材料的一个重要特征就是在固体状时,在一定温度或载荷下会发生相变过程。因此在摩擦过程中,当法向载荷够大时,局部发生的相变将导致接触点材料力学性质改变,从而使摩擦性能改变。在单点接触的Hertz模型的基础上,建立以钢球接触Ni-Ti记忆合金平面的接触模型,通过分析法向载荷诱发塑性变形的过程,探讨法向载荷对Ni Ti形状记忆合金(Shape memory alloy,SMA)摩擦过程的影响,并与实验结果进行比较。理论分析和实验研究结果均表明:当法向载荷小时,摩擦因数与法向载荷成负相关;当法向载荷超过一定值后,摩擦因数几乎不变。所得出的结论可以用来预测形状记忆合金的摩擦性能,以控制和减少零件可能因磨损造成的损失。更多还原

【Abstract】 An important characteristic of shape memory alloy( SMA) is that under the effect of a certain temperature or load,phase changes of this material occur in the solid form. Therefore,during the process of friction when the normal load is great enough,phase transformation locally occurs within the actual contact area,resulting in changes in mechanical properties of the material at the point of contact,thus altering the friction feature. Based on a single point contact Hertz model,the contact model with a steel ball contacting the Ni-Ti flat surface was established. By analyzing the process of plastic deformation induced by the normal load,the influence on the friction process of Ni-Ti SMA by normal load was discussed,and the results were compared with that from experiments. Both of theoretic and experimental results indicate that,when the normal load is small,the friction coefficient is inversely proportional to the normal load,and when the load exceeds a certain value,the friction coefficient is almost unchanged. The research conclusion can be used to predict the friction property of SMA,so as to control and reduce the wear caused losses of the parts.更多还原