Enhancement of Wear Properties of Ultrafine-Structured Al–Sn Alloy-Embedded Sn Nanoparticles Through In Situ Synthesis

An in situ displacement reaction was used to prepare an Al–12 wt% Sn nanocomposite alloy from mechanically alloyed Al–SnO 2 –MgH 2 . The nanoscaled Sn phase was mostly 30–50 nm in size and was distributed uniformly in the Al matrix. The wear properties of the Al–SnO 2 –MgH 2 composite were enhanced significantly compared to those of an Al–Sn–MgH 2 composite. These improvements stemmed from the high-strength and nanoconfined Sn-phase lubrication, which moved the peak stress far below the surface, released strain localization at the uppermost sliding surface layer, and suppressed cracking and surface roughening. The dispersion strengthening of the Al–SnO 2 –MgH 2 composite favored the maintenance of a stable tribolayer, which resulted in an integrated worn surface and an excellent wear performance.