Al-Cu-Mn-Zr-Cr Creep Resisting Alloys: Microstructure and Mechanical Properties

摘要

We studied the effect of composition and technological parameters on the structure and mechanical properties of ingots and hot-rolled sheets of Al-Cu-Mn-Zr-Cr alloys at room and elevated temperatures. It is shown that the solubilities of zirconium and chromium in the aluminum solid solution in 20 X 40 X 180 mm ingots obtained under specific melting conditions may reach up to 0,8 wt. percent. Heating at temperatures below 450°C leads to the formation of fine dispersoids of the Al_3Zr and Al_(20)Cu_2Mn_3 phases characterized by high thermal stability. As promising compositions, we suggest Al-2.5 percent Cu-0.8 percent Zr-0.8 percent Cr and Al-2.5 percent Cu-1 percent Mn-0.5 percent Zr-0.5 percent Cr, which, in the form of hot-rolled sheets, surpass an A2219-type alloy in mechanical properties at room and elevated temperatures (350-400 deg C).