摘要
The micros tructural evolution and mechanical properties of a new Al-3.8 Cu-1.2 Li-0.4 Mg-0.4 Zn-0.4 Ag-0.3 Mn-X alloy treated at different solution temperatures were investigated.The grain size was measured in optical micrograph(OM).The residual particles and the major precipitates were identified by electron probe microanalysis(EPMA),scanning electron microscopy(SEM) and transmission electron microscope(TEM),respectively.The results show that the peak strength appears at 530℃/1 h+T6(165℃/20 h) and the values are 566.2 MPa(tensile strength) and 538.2 MPa(yield strength) with the elongation of 6.5 %.The strength of the alloy increases rapidly with the amount of the precipitates T1 and θ’ increasing when the solution temperature is530℃.The increase in density of precipitates is resulted from the residual particles Al2 Cu,and particles enriched with Cu,Mg,Zr and Ag dissolve into matrix gradually with the solution temperature increasing.Finally,the number of precipitates decreases and part of the grain boundary weakens with a further increase in solution temperature from 540 to 550℃,leading to a decline of strength.
基金
financially supported by the National High-Tech Research and Development Program of China(No.2013AA032401)。
