基于脉冲回波法的反应烧结碳化硅弹性模量预测

Prediction of elastic modulus of reaction bonded silicon carbide based on pulse-echo method

为了快速准确地检测反应烧结碳化硅(RBSC)的弹性模量,基于材料超声声速与弹性特性之间的关系,采用脉冲回波法检测不同密度RBSC材料的超声纵波声速与横波声速,结合密度计算得到材料的弹性模量。建立了弹性模量与密度之间的直接模型,并将模型预测值与实测值、传统经验模型所得值分别作对比;进一步,研究了不同密度RBSC材料的面孔隙率和游离硅含量随密度的变化规律,并建立了密度与游离硅体积百分含量的经验公式。结果表明,建立的弹性模量预测模型可以无损、简单、快捷地得到RBSC材料的弹性模量,密度与游离硅体积分数的经验公式还可辅助调节RBSC材料的制备工艺,对碳化硅等复合材料的研制和检测具有重要意义。

To quickly and accurately detect the elastic modulus of the reactive bonded silicon carbide(RBSC),the pulse-echo method was used to detect the ultrasonic longitudinal wave velocity and shear wave velocity of RBSC of different densities based on the relationship between the ultrasonic wave velocity and elastic properties of the material.The elastic modulus of the material was further obtained by the density calculation.The direct model between the elastic modulus and the density was firstly established.As long as the density of RBSC was known,the elastic modulus can be rapidly and directly used to predict its elastic modulus value.To verify the reliability of the model,this paper compared the predicted values of the model with the measured values and the values obtained by the traditional empirical model.Furthermore,the relationship between the areal porosity and free silicon content of RBSC with different densities was investigated and an empirical formula of the density and the free silicon volume percentage content was established.Results showed that the elastic modulus prediction model established in this paper can not only obtain the elastic modulus value of RBSC quickly but was also conducive to the adjustment of the RBSC preparation process,combining with empirical formula of the density and the free silicon volume percentage content.It is important for the development and detection of composite materials such as silicon carbides.