The microstructure, mechanical and corrosion properties of calcium polyphosphate reinforced ZK60A magnesium alloy composites

The calcium polyphosphate (CPP) reinforced ZK60A magnesium-matrix composites are fabricated using powder metallurgy. In this study, the microstructure, mechanical and corrosion properties of the composites are investigated. The CPP particles are uniformly distributed throughout the composite with firmly bounded CPP–matrix interface. The composites consisted of 20 wt.% CPP achieved a maximum compressive strength of 494.88 MPa. Effective load transfer from matrix to particle results in particle fracture observed during compressive tests. Tensile tests show that the ultimate strength and yield strength of the composites were reduced by CPP addition. The fracture surfaces of composites observed during tensile tests show matrix deformation, interfacial detachment and particle breakage coupled with microscopic crack. The composites enhance the corrosion resistance of materials and exhibit a more uniform corrosion attack in immersion tests and electrochemical tests. Furthermore, CPP accelerates the precipitate of hydroxyapatite in the composites. These results suggest that the CPPp/ZK60A composite is a promising candidate for degradable implant materials.