| Cu-Cr-Zr alloy has excellent physical and mechanical properties because of the effect of aging precipitation.Equal channel angular press(ECAP)methods can generate uniform ultra-fine-grained bulk materials that offer extraordinary properties,which has led to the development of Cu-Cr-Zr alloy in many engineering fields.The evolution of crystallographic texture and the micro structure of Cu-Cr-Zr alloy subjected to ECAP were investigated using Electron back-scattered diffraction(EBSD)and X-ray(XRD)analysis.The mean grain size,the grain size distribution and the distribution of the boundary orientation angles were determinated by the collected EBSD data.The texture was represented by the orientation distribution function(ODF).Tensile tests at a strain rate of 1mm/min were performed on a Ins-tron 8801 machine.The results show that Cu-Cr-Zr alloy with ultra-fine grains(UFG)of 200 nm diameter was successfully processed by 8-passes ECAP at room temperature via route Bc.The EBSD results show that the texture orientation mainly consists of Copper type{111}<112>,S type {124}<634> and Cube type {001}<100> with the maximum intensity of ~8.69 after 4 ECAP-passes.The primary texture orientation are Brass type{112}<1 1 0> and {101}<10 1 > texture with the maximum intensity of ~6.22 after 8ECAP-passes.The texture intensity decreases compared with the 4 passes.The results of XRD show that the texture orientation of Cu-Cr-Zr alloy exhibit the strong mono-clinic symmetry after the first pass in the ODF figures.The texture orientation gradually tend to saturate and the maximum texture intensity is 6.96 after 4and 8 ECAP-passes respectively,which is in a good agreement with EBSD test.The texture orientation of aged Cu-Cr-Zr alloy performs certain cyclicity and regularity due to the repetition of the pressing path.The excellent overall properties of Cu-Cr-Zr alloy were achieved by 8ECAP-passes specimen and aged at 430℃ for 3h.The tensile strength,hardness and elongation are 614 MPa,190HV and 23% respectively,and the electrical conductivity increases to 80%IACS.The dispersed precipitates inhibit the dislocation.The mechanical properties and electrical conductivity enhance through ECAP followed by aging due to the effect of precipitates.Strengthening mechanisms resulting from fine-grains strengthening,dislocation strengthening and precipitation-strengthening through ECAP and subsequent aging.The main strengthening mechanism include fine-grain strengthening and dislocation strengthening after the first pass of ECAP.The precipitation-strengthening significantly improves the ultimate strength after 8 passes because the generation and annihilation of dislocation reaches to be balance and the grain size can not be further refined. |
