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在金属板表面引入一恒稳电流,即可在板中形成一电流场.通过求解这一电流场的分布方程,再经化简、积分后得到了金属板表面任意两点间电位差和板材电阻率之间的数学关系式.将Hashin得出的金属基复合材料体积分数和电阻率之间的关系式代入以上结果后得出了金属基复合材料板材的电阻率和体积分数之间的关系式.利用四探针探头和恒流源对这一计算公式进行了验证.用计算机模拟不同电阻率、不同板材厚度以及不同四探针相对距离的变化,得出了应测得电位差随之变化的理论曲线.对有缺陷的金属基复合材料板材测算结果表明这一方法可以发现材料内部存在的疏松、体积分数不均匀、分层等缺陷.
By introducing a constant current into the surface of the metal plate, a current field can be formed in the plate.Through solving the distribution equation of the current field, the potential difference between any two points on the surface of the metal plate and the plate The relationship between the resistivity of the mathematical relationship between the volume fraction of the metal matrix composite obtained by Hashin and the resistivity of the relationship between substituted into the above results obtained metal matrix composite sheet resistivity and volume fraction relationship The formula was verified by the four-probe probe and the constant current source.The simulation of different resistivities, different plate thicknesses and the relative distances between different four probes by computer simulated the potential difference The results show that the method can find defects such as loose internal volume, uneven volume fraction and delamination in the material.