Wear-resistance enhancement of nanostructured W-Cu-Cr composites

Nanostructured W-Cu-Cr composites were fabricated, which exhibit exceptionally high hardness (similar to 1000 HV) as compared with those of the conventional W-Cu composites, due to the combined advantages of Cr dissolution, precipitate formation and grain refinement. Nonmonotonic variation of the wear resistance with hardness was discovered. With an appropriate content of Cr, the preferential oxidation reduced the oxidation of W. Moreover, it facilitated formation of a stable protective film with fish-scale morphology and also refined the structure, leading to a high microhardness at the worn surface. The wear rate (1.65 x 10(-6) mm(3) N-1 m(-1)) was reduced by an order of magnitude compared with that of the conventional counterpart. However, excessive addition of Cr may deteriorate the wear resistance in spite of a higher hardness due to the embrittlening of W phase and difficulty to form a stable protective film at the worn surface. This study provides a new strategy for developing W-Cu composites with outstanding wear resistance.

Automated summary

Nanostructured W-Cu-Cr composites with exceptionally high hardness were fabricated in this study, showing nonmonotonic variation of wear resistance with hardness. The appropriate content of Cr facilitated the formation of a stable protective film, leading to higher microhardness at the worn surface and reduced wear rate. Excessive addition of Cr, however, may deteriorate wear resistance despite higher hardness.