A study on Mg wires/poly-lactic acid composite degradation under dynamic compression and bending load for implant applications.

A novel and economic device is developed for simulating the physiological mechanochemical conditions. The degradation behaviors of poly-lactic acid (PLA) based composite reinforced with magnesium alloy wires (Mg wires/PLA) under dynamic compression and bending loads are investigated. The results denote the dynamic loads significantly influence the degradation behaviors of the composite. The dynamic bending load would profoundly promote the degradation of Mg wires in the composite and then accelerate the mechanical properties loss of the composite. The bending strength retention of the composite under consistent dynamic bending load at a magnitude of 5.6 N (about 5.6 MPa for the maximum stress at the middle surface) after 21 days immersion is about 53.3%, comparing to 69.7% for the dynamic compression load at a magnitude of 12 N (0.5 MPa for the compression stress). Furthermore, a numerical model is successfully postulated to elucidate the bending strength evolution of the composite under different dynamic loading conditions.