Tomographic investigation of the effects of second phases on the biodegradation and nano-mechanical performance of a Mg-Zn-Ca alloy
A combination of 3D tomography techniques provides direct evidence that links the phase assemblage to the bio-corrosion behaviour of a magnesium-zinc-calcium (Mg-Zn-Ca) alloy. The true shape, connectivity and volume fraction of the components have been determined using focused ion beam (FIB) tomography. The mechanism of the effect of the components with different morphologies on biodegradation was studied with the help of FIB. Micro X-ray CT (MicroCT) was used to investigate the degradation of the magnesium (Mg) alloys after 10 days’ immersion in simulated body fluid (SBF). Furthermore, the second phases affect the mechanical performance of the alloys. Nanoindentation was used to evaluate the nanohardness and elastic modulus of the eutectic products. The amount of second phase, however, is the key controlling factor in the bio-corrosion behaviour: any effect of configuration is undetectable.