Fretting wear of Mg–Li–Al based alloys

•Fretting behavior of novel Mg–Li–Al based alloys (LATZ9531 and LATZ971).•Systematic study on the effect of loading, slip amplitude and oscillation frequency.•Central cracking in LATZ9531 with adhesive and delamination wear.•Enhanced performance of LAT971 compared to that of LATZ9531 at higher loading.•Tribo-oxidation renders protection through surface oxide.

The fretting wear behavior of newly developed Mg–Li–Al based alloys LAT971 and LATZ9531 is investigated by using reciprocating fretting wear testing under dry condition with varying number of cycles (10–104), normal load (1–10 N), oscillation frequency (1–9 Hz), and displacement amplitude (80–200 µm). The worn surface is characterized by scanning electron microscopy to reveal wear mechanisms governing under each condition. Overall, results show that LATZ9531 elicits consistent performance, lower coefficient of friction (~0.50) than conventional AZ31 (~0.69) and LAT971 (0.60). But, under the condition of high normal load (of 10 N), LAT971 shows least wear volume loss (~0.05 mm3) as well as lower coefficient of friction (~0.26) compared to that of LATZ9531 or conventional AZ31. In addition to central cracking in LATZ9531, mainly adhesive and delamination wear mechanism are noticed. Under frequency variation LAT971 shows enhanced performance especially at high frequency (~9 Hz). However, with increase in slip amplitude (~200 μm), the major wear mechanism is observed to be abrasive and oxidative wear, wherein LATZ9531 shows least wear volume. Friction hysteresis of increasing slip amplitude shows increase in energy consumption during fretting wear, and its shape confirms that in spite of change in stroke lengths, fretting is occurring in the gross slip regime.