Variation of the Thermal Stress in the Al₁₈B₄O_33W/Al Composite during Low Temperature Cycling

抄録

With the method for measurement of triaxial stress in material by the X-ray diffraction, the variation of the thermal stress of matrix in a 25 vol%Al₁₈B₄O_33W/6061Al composite during low temperature cycling was investigated. It was found that the matrix of composite undergoes a process of tensile mismatch plastic strain when cooling, while it undergoes a process of unloading for mismatch stress when warming. After low temperature cycling, the thermal residual stress of composite was decreased obviously. If the secondary low temperature cycling was carried out, the thermal residual stress can be decreased again when the temperature of secondary cycling is lower than that of the first cycling.