Effect of Mo, Zr, and Y on the high-temperature properties of Al-Cu-Mn alloy

摘要

Mo, Zr, and Y with low diffusion coefficients in Al matrix were used to improve the high-temperature properties of the Al-5.8Cu-0.3Mn- 0.2Mg alloy. The effects of these microalloying elements on the microstructures of the Al-5.8Cu-0.3Mn-0.2Mg alloy were investigated with the aid of optical microscopy and high-resolution transmission electron microscope (HRTEM). The HRTEM images and selected area electron diffraction patterns indicated that L12-Al3(Zr, Y), Al3Zr, Al3Y, and Al12Mo could precipitate in the process of solid solution treatment after adding Mo, Zr, and Y. These Mo-, Zr-, and Y-containing precipitates were stable at high temperatures and could slow the coarsening rate of h9 precipitates at high temperatures. The tensile strength of the Al-5.8Cu0.3Mn-0.2Mg alloy modified by Mo, Zr, and Y microalloying elements was improved significantly at both room and high temperatures. The strengthening mechanisms were discussed in detail.