Abstract:

A phenomenon was found by experimental results that the same size of cylindrical parts had different radial and axial thermal deformations under the same conditions. And the traditional therodynamic theory could not explain this phenomenon. The relationship between volume expansion coefficient and linear expansion coefficient of crystal was built up by using the Lattice vibration theory of solid-state physics. Based on this relationship, a radial thermal deformation of cylindrical model was set up. The model was different with the traditional model. The experimental results show that the value which calculated by the model is closer to the experimental results than that by the traditional model, and cylindrical parts have different radial and axial thermal expansion coefficient. Traditional model of axial thermal deformation can not be used in micro-field when calculating the radial thermal deformation of cylindrical parts.

Key words: linear expansion coefficient;volume expansion coefficient;radial thermal deformation of cylindrical part, abnormal phenomena

摘要：

通过实验发现了直径和长度相同的轴在径向和轴向具有不同的热变形量，传统的热力学理论不能解释这一现象。利用固体物理学晶格振动理论，推导了晶体体积膨胀系数与线膨胀系数之间的关系;将金属材料近似为晶体材料，利用线膨胀系数与体积膨胀系数的关系并结合对材料线膨胀系数研究的成果，建立了轴类零件径向热变形模型，理论分析证实了轴类零件径向热膨胀系数与轴向热膨胀系数不同。实验结果表明：轴类零件径向热变形模型计算结果较传统热力学计算结果更接近实验结果，且径向和轴向具有不同的热膨胀系数，在高精度领域，轴类零件的径向热变形不能使用轴向热膨胀系数进行计算。

关键词: 线膨胀系数, 体积膨胀系数, 轴类零件径向热变形, 异常现象