Microstructural investigation on B4C/Al-7093 composite

The microstructures of B4C/Al-7093 composites synthesized using the Boralyn technique were investigated. The present results show that the B4C particles were distributed uniformly in the aluminum matrix. SEM fractographic investigation revealed that particle cracking was a dominant damage mechanism, indicating a strong B4C/Al interfacial bond which promoted high mechanical properties in the composite. TEM and EDS analyses showed MgO particles at and near the B4C/Al interfaces. The amount of MgO significantly influenced the microstructure of the matrix. The formation of MgO in the composite resulted in the depletion of the Mg atoms in the matrix and furthermore, the suppression of precipitation during the aging process.