DEVELOPMENT OF MICROSTRUCTURE, MECHANICAL AND WEAR CHARACTERISTICS OF THE BRASS ALLOY PROCESSED BY ECAP

Abstract

In the present study, the microstructure, mechanical and wear characteristics of commercial Cu-30Zn brass alloy were developed by an equal channel-angular process (ECAP) using a particular die in constant dimensions. The ECAP process was experimentally conducted at room temperature using (1-4) passes in route C with lubricating conditions. Also, the post-annealing treatment at 350 oC has been done for some brass samples, which were deformed with four passes. Findings revealed that by conducting the ECAP, a significant reduction in the grain size of the deformed brass samples is achieved compared to the as-received alloy. The grain refinement increased with the increasing number of ECAP passes. However, the post-annealing treatment increased the grain size of the deformed brass alloy, but still it was lower than the as-received alloy. Moreover, the mechanical performance, i.e. micro-hardness and strength, was significantly enhanced after the ECAP. The samples processed with three passes presented the highest hardness value (237 HV) and mechanical strength (UTS= 692 MPa, and YS= 542 MPa) due to the homogeneous strain hardening and substantial grain refinement throughout the ECAP process. However, the micro-hardness and mechanical strength of brass alloy decreased after post-annealing treatment compared to those of the ECAP deformed samples. The elongation to failure also decreased greatly with increasing the number of passes of ECAP. Additionally, the wear resistance of the investigated samples increased significantly after increasing the number of ECAP passes compared to the as-received alloy. The highest wear resistance has been achieved for samples deformed by three and four passes of ECAP due to the considerable grain size refinement and higher hardness. However, a slight increase in the wear rate occurred after post-annealing treatment on a brass alloy sample processed with four passes due to the increase in grain size.