Dry-sliding tribological behavior of Fe–28Al–5Cr/TiC composites

Dry-sliding tribological performance of the Fe–28Al–5Cr and its composites containing 15, 25, 35, 50 wt.% TiC, produced by hot-pressing process, was investigated against an AISI 52100 steel ball in ambient environment at varying applied load and sliding speed. It can be found that the coefficient of friction (COF) is irrespective of TiC content and applied load, but increases from 0.46 to 0.60 with increasing sliding speed at the given testing conditions. The wear-resistance increases with an increase of TiC contents. Impressively when TiC amount reaches 50 wt.%, the wear-resistance improves about 4–30 times compared to the pure Fe–28Al–5Cr at different sliding parameters. The wear rates of all the materials increase mildly with an increase in applied load, but are nearly independent of the sliding speed at an applied load of 20 N. The wear rates of the all materials are on the order of 10−3–10−4 mm3 m−1. In a word, the addition of the TiC can improve significantly the dry-sliding wear-resistance of the Fe–28Al–5Cr intermetallics at room temperature. The enhanced wear-resistance is attributed to the high hardness of the composites and as well hard TiC phase play a role of load-carrying. Worn surface features of all the materials were examined using a scanning electron microscopy (SEM). The dominant wear mechanism of Fe–28Al–5Cr and 15% composite was flaking-off, but those of 25–50% composites was flaking-off and plowing.

► TiC improves significantly the dry-sliding wear-resistance of Fe-28Al-5Cr alloy. ► Wear rate of the composite with 50% TiC is 4-30 times lower than the pure Fe-28Al-5Cr alloy. ► Enhanced wear-resistance of below 15% TiC composites is attributed to high hardness. ► Enhanced wear-resistance of over 25% TiC composites originates from load-carrying role of TiC.