Abstract: A two-step process for joining a first part to a second part, the first part having a coefficient of thermal expansion lower than the coefficient of thermal expansion of the second part. An anchor layer is then brazed at a lower temperature to the first part having a high thermal expansion coefficient. The anchor layer has a thickness such that upon cooling it will yield to relieve stress build up resulting from the differing thermal expansion coefficients between it and the first part. The anchor layer is then brazed to the part having a high thermal expansion coefficient. The process is particularly useful for joining carbon-carbon composite parts to copper substrates for use in the manufacture of high temperature heat exchangers as used, for example, in nuclear fusion reactors.