Mg-based metallic glass matrix composite with in situ porous titanium dispersoids by dealloying in metallic melt

A Mg3Cu3Gd bulk metallic glass matrix composite with porous α-Ti dispersoids was prepared by dealloying in a metallic melt. The in situ formed α-Ti dispersoids had a pore-size of ∼500 nm, which was imparted from the Ti2Cu precipitate in the prealloy. Pore size was therefore controllable through the cooling rate of the prealloy preparation. Plasticity was not improved apparently, however the maximum fracture stress under four point bending mode increased from 217 MPa for the monolithic counterpart to 387 MPa. This was due to the optimal relationship where dispersoid size (L)≈dispersoid interval distance (S)≈process zone size (Rp). This was achieved locally within and around the porous Ti dispersoids, and helped improve the toughness and ductility.