Papers by Author: Xiu Yu Wei

Abstract: A systematic homogenization treatment on Al-Li-Cu-Mg-Mn-Zr alloy, within the temperature range from 500
C to 540
C for 24h or 36h was conducted. Microstructure and alloying elements distribution before and after homogenization treatment were studied by optical microscope, SEM, EDS and XRD. The results showed that in the as-cast condition Cu segregated at grain boundary and formed θ(Al2Cu) phase. With the homogenization temperature increased and time prolonged, the amount of the remained particles at grain boundaries decreased, and the alloying elements distribution became more homogeneous. It has been found that the homogenization temperature has more obvious effects on the microstructure and mechanical properties than time. However, the alloy homogenized at temperatures above 540
C was overheated. Furnace cooling generates large amounts of precipitates in the matrix. The best homogenization parameter of the Al-Li-Cu-Mg-Mn-Zr alloy was determined as 530
C for 24 h followed by air cooling.

Abstract: The effects of trace Ce, Ag on the microstructure and mechanical properties of Al-Cu-Li alloy after thermal exposure have been investigated. It’s found that the addition of Ce may lead to a slight increase in mechanical properties after thermal exposure at 107  . The stability of T1 phase is enhanced by independent Ag addition and the combined additions of Ag and Ce,which results in higher strength compared with Ag-free alloy at 150  thermal exposure. However, at 200  exposure, a great number of q¢ precipitates at the expense of T1 may be responsible for higher tensile strength in the Ag-free alloy than that of the independent addition of Ag and combined additions of Ag and Ce alloys.