Influence of spark plasma sintering on microstructure and corrosion behaviour of Mg-4Al-2RE for biomaterials

Abstrakt

Gas atomized powder and then the as-milled powder was sintered at temperatures in the range of 400- 550 °C and holding time up to 3 or 10 minutes. The effect of sintering parameters on the microstructure was investigated by scanning and transmission electron microscopy.

Mechanical strength was investigated by microhardness measurements. Corrosion properties were studied by linear polarization method.

The sintering temperature influences significantly microstructural evolution. The application of relatively high load during sintering caused deformation of individual particles and consequent recrystallization.

The increase of sintering temperature resulted in the relaxation of the internal strain and in grain growth. The increase of the sintering temperature resulted also in a pronounced dissolution of secondary phase particles followed by globularization of this phase.

Due to the pronounced recrystallization with an increasing temperature a considerable loss of mechanical strength occurred. Nevertheless, the behaviour of corrosion resistance was more complex and strongly influenced by temperature and holding time.

Generally, the corrosion resistance increased with increasing temperature.