Effect of Ti content and hot/cold extrusion on microstructure and properties of 2219 heat-resistant aluminum alloy

The effects of Ti and hot/cold extrusion on the microstructure and properties of the 2219 heat-resistant aluminum alloy were studied in this paper. The results show that the grain size decreases significantly with the increase of Ti content of the three hot-extruded alloys, and the alloy with 0.49Ti has the best mechanical properties. The hardness and tensile strength at room temperature are further improved. Besides, the peak value of thermal compression stress reached up to 252.76 MPa at 250 degrees C and the maximum intergranular corrosion depth is 181.56 mu m. Compared with the hot-extruded materials, the strength and heat resistance of the cold-extruded materials are both enhanced significantly. The tensile strength is increased by 32% to 416.67 MPa at room temperature and the peak value of thermal compression stress reached up to 230.82 MPa at 250 degrees C. Besides, the maximum intergranular corrosion depth was also decreased by 81.09 mu m. The mechanical properties of alloys can be further improved by the addition of titanium and cold extrusion to meet the requirements of machines worked at high temperature in the industry.