Tribological behavior of Fe₇₀Ni₃₀ alloy with nanoscale twins under liquid paraffin lubrication

Fe₇₀Ni₃₀ alloy with nanoscale twins was obtained by deep cryogenic treatment (DCT) of coarse grained Fe₇₀Ni₃₀ alloy (CG-Fe₇₀Ni₃₀) at liquid nitrogen temperature. The tribological behavior of DCT-Fe₇₀Ni₃₀ alloy was investigated under liquid paraffin oil lubrication compared with that of CG-Fe₇₀Ni₃₀ alloy. The experimental results showed that the wear resistance of DCT-Fe₇₀Ni₃₀ alloy was improved significantly after the introduction of nanoscale twins, and DCT-Fe ₇₀Ni₃₀ alloy also showed a little lower friction coefficient relative to CG-Fe₇₀Ni₃₀ alloy. The results indicated that twins play a positive role in the material's friction-reduction and anti-wear properties, which is attributed to the better oil-adsorption ability and enhanced hardness of DCT-Fe₇₀Ni₃₀ alloy caused by structural refinement. Wear mechanisms were discussed.