Antimicrobial and wear performance of Cu-Zr-Al metallic glass composites

The antimicrobial and wear behaviour of metallic glass composites corresponding to the Cu50 + x(Zr44Al6)50 − x system with x = (0, 3 and 6) has been studied. The three compositions consist of crystalline phases embedded in an amorphous matrix and they exhibit crystallinity increase with increasing Cu content, i.e., decrease of the glass-forming ability. The wear resistance also increases with the addition of Cu as indirectly assessed from H/Er and H3/Er2 parameters obtained from nanoindentation tests. These results are in agreement with scratch tests since for the alloy with highest Cu content, i.e., Cu56Zr38.7Al5.3, reveals a crack increase, lower pile-up, prone adhesion wear in dry sliding and higher scratch groove volume to pile-up volume. Samples with higher Cu content revealed higher hydrophilicity. Time-kill studies revealed higher reduction in colony-forming units for E. coli (gram-negative) and B. subtilis (gram-positive) after 60 min of contact time for the Cu56Zr38.7Al5.3 alloy and all the samples achieved a complete elimination of bacteria in 250 min.