MICROSTRUCTURAL EVOLUTION OF Al-Cu-Mg-Ag ALLOY WITH TRACE Zr ADDITION DURING TWO-STEP HOMOGENIZATION
The microstructural evolution in an Al-Cu-Mg-Ag alloy with trace Zr addition during homogenization treatment was characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). It was shown that the low-melting-point phase segregating toward grain boundaries is Al2Cu, with a melting point of 523.52℃. A two-step homogenization process was employed to optimize the microstructure of the as-cast alloy, during which the alloy was first homogenized at a lower temperature, then at a higher temperature. After homogenized at 420℃ for 6 h, Al3Zr particles were finely formed in the matrix. After that, when the alloy was homogenized at an elevated temperature for a longer time, i.e., 515℃ for 24 h, most of the precipates at the grain boundaries were removed. Furthermore, the dispersive Al3Zr precipitates were retained, without coarsening greatly in the final homogenization step. A kinetics model is employed to predict the optimal homogenization time at a given temperature theoretically, and it confirms the result in present study, which is 420℃/6h+515℃/24h.
Al-Cu-Mg-Ag alloy two-step homogenization Al3Zr Al2Cu
FEIYUE MA ZHIYI LIU
School of Materials Science and Engineering, Central South University, Changsha 410083 Peoples Republic of China
国际会议
第五届先进材料与加工国际会议(Fifth International Conference on Advanced Materials and Processing ICAMP-5)
哈尔滨
英文
855-862
2008-09-03（万方平台首次上网日期，不代表论文的发表时间）