Neutron diffraction measurements of residual stresses in metal matrix composite samples

The results of neutron diffraction experiments for the determination of residual stresses in metal matrix composite samples are reported. Investigated materials are At alloys (AA2124 and AA359) with SiC particulate reinforcements. An AA2124 + 17% SiCp forged specimen and an AA359 + 20% SiCp bar, one side of which was submitted to a spark-erosion treatment, were investigated at LLB, Saclay (F) and ILL, Grenoble (F), respectively. In both cases, residual stresses were determined in both the matrix and the reinforcement, in different gauge points. As expected, for both the samples, results show that in each gauge point the main contribution is generally given by thermal microstresses. In the case of the AA359 + 20% SiCp bar, a slight decrease of the absolute value of residual stresses (tensile in the matrix, compressive in the reinforcement) is found, when approaching the spark-eroded face of the specimen. (C) 2001 Elsevier Science Ltd. All rights reserved.