Effects of rolling method on the microstructure and anisotropy of mechanical properties of Cu–15Cr in-situ composites

Abstract

The effects of unidirectional rolling (UR) and cross rolling (CR) on the Cr phase morphology, texture, and anisotropy of mechanical properties of Cu–15Cr in situ composites were investigated by using optical microscope, x-ray diffraction, and quasi-static compression techniques. The results showed that the elongation of the Cr phase in the UR specimen (49.2 μm) was greater than that of the CR specimen (18.6 μm) in the rolling direction after rolling with a reduction of 86.7%, while the elongation of the Cr phase in the UR specimen (10.9 μm) was slightly lower than that of the CR specimen (11.7 μm) in the transverse direction. The volume fraction of the Goss texture component of the Cu matrix was the largest in the UR specimen (31.3%), while that of the Brass texture component was the largest in the CR specimen (28.0%). The approximate ∼ (102)[2‾2‾1] texture component (14.2%) was present in the CR specimen. The results of Sachs model calculations indicated that the anisotropy of the compressive yield strength of the CR specimen (10.8%) was greater than that of the UR specimen (6.8%) due to the difference in texture components. The critical stress required to cross the Cu/Cr phase interface was calculated and indicated that the presence of the fibrous Cr phase made the anisotropy of the compressive yield strength of the CR specimen (21.9%) lower than that of the UR specimen (32.7%). The difference in the anisotropy of the compressive yield strength of the two specimens was reduced by the competition between these two factors, and eventually, the anisotropy of the compressive yield strength of the UR specimen (17.7%) was slightly higher than that of the CR specimen (14.1%), indicating that the effect of the fibrous Cr phase on the compressive yield strength anisotropy was greater than that of the texture.