Formation of Fe–Al Intermetallic Compound Layer by AIH-FPP and its Effect on Tribological Properties of Stainless Steel

Abstract

In order to increase the surface hardness and improve the tribological properties of stainless steel, Fe-Al intermetallic compound layers were created by atmospheric-controlled induction-heating fine particle peening (AIH-FPP). The surface microstructure of the stainless steel treated with AIH-FPP was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and micro-Vickers hardness testing. In addition, the tribological properties were investigated by reciprocating ball-on-disk wear tests. When high-speed steel particles coated with thin aluminum layers were used as the shot particles, Fe-Al intermetallic compound layers were formed at the surfaces of the stainless steel with increased heating time during AIH-FPP. This is because aluminum was transferred from the shot particles, and the temperature at the treated surface increased as a result of a combustion synthesis reaction. When the heating temperature after FPP was increased, the transferred aluminum and nitrogen in the atmosphere reacted, which resulted in the formation of aluminum nitrides in addition to Fe-Al intermetallic compounds. The tribological properties of the stainless steel were improved by AIH-FPP since high-hardness layers were created. The results indicate that the formation of an Fe-Al intermetallic compound layer with high hardness by AIH-FPP is effective for modifying the tribological properties of the stainless steel within a relatively short span of time.

Development of AIH-FPP Carburizing Process Using Carbon Powder

“…9,10) Combustion synthesis reactions occurred when aluminum or titanium particles were used, and intermetallic compound layers with high wear resistance and high-temperature oxidation resistance were formed. 11,12) When high-speed tool steel particles with high hardness were shot to the surfaces of structural steels heated to recrystallization temperatures, surface layers containing fine grains with diameters of several micrometers were created owing to dynamic recrystallization, which improved the fatigue properties of AIH-FPP-treated steel. 13) This procedure can be applied to materials that are difficult to refine using only thermal treatments.…”