| Sliding wear tests of ordered Fe-28 at.% Al alloys with B2 and DO₃ structures have been carried out under various environmental conditions to investigate the effect of water (H₂O) on the sliding wear behavior of the alloy. The wear rate of the ordered alloy under wet (water lubricated) condition was found to be much lower than that under dry condition. The sliding-wear-test result was quite different from the abrasive-wear-test result, which reported higher wear rate under the wet condition. It was also observed that the higher the humidity of the ambient air, the lower the wear rate of the Fe-Al alloy becomes. SEM observations revealed that micro ploughing with some micro cutting was a major wear mechanism of the alloy under the wet condition, while under the dry condition with varying humidity, delamination and oxidation wear were two major wear mechanisms. It was found that during the sliding wear of the Fe-Al alloy, unlike during the three-body abrasive wear, water functioned as a lubricant under the test conditions and accelerated formation of the oxide layer. The water is found to decrease the sliding wear rate of the Fe-Al alloy, instead of increasing the rate by embrittling the ordered alloy. |
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