In-situ formation of Zn oxide particles in CuZn matrix during friction stir processing

摘要

Cu-30Zn plates were friction stir processed at a rotational speed of 1120 rpm and a traverse speed of 50 mm/min. Two kinds of samples were produced. The first sample was friction stir processed without using a secondary phase. In the case of the second sample, Al(2)O(3)particles were incorporated into the Cu-30Zn plates to produce a surface nanocomposite. In the absence of Al(2)O(3)particles, the produced sample showed the typical microstructures of friction stir processed brass alloys. However, in the presence of Al(2)O(3)particles, the SZ showed a bimodal grain structure, and Zn oxide particles were formed. The high heat input condition of FSP caused the evaporation and scape of Zn from the CuZn matrix. The evaporated Zn reacted with oxygen of the air entrapped between the Al(2)O(3)particles, which formedin-situand encapsulated Zn oxide particles. This phenomenon has not been yet reported in the literature.