Cailiao gongcheng (Nov 2023)
Effect of solid solution temperature on microstructure and properties of 2050 Al-Li alloy extruded bars
Abstract
Under certain solid solution time conditions, the solid solution temperature determines the degree of supersaturation and recrystallisation of the matrix after quenching, and is an important factor in enhancing the performance of the material after aging treatment. Through the solid solution heat treatment of 2050 Al-Li alloy extruded bar at different temperatures for 2 h and artificial aging treatment at 170 ℃ for 40 h, combined with a variety of property testing methods and microstructure observation methods, the effect of solid solution temperature on the microstructure and properties of 2050 Al-Li alloy extruded bar was studied. The results show that the residual phase is continuously redissolved with the increase of the solid solution temperature, and the residual phase is mainly iron-containing phase when the solid solution temperature is 525 ℃.The slight overheating structure appears in the bar when the solid solution temperature is 550 ℃, and the serious overheating structure appears in the bar when the solid solution temperature reaches 570 ℃. Local recrystallization occurs when the bar is heated to 500 ℃, and complete recrystallization occurs when the solid solution temperature reaches 570 ℃. When the 2050 Al-Li alloy extruded bars are solution treated at different temperature (450-550 ℃) and aged at 170 ℃ for 40 h, the number of θ′ and T1 phases increases with the increase of solid solution temperature, and the strength increases rapidly and then slowly, when the solution treatment temperature is 550 ℃, the yield strength and tensile strength of extruded rods are the highest, which are 505 MPa and 567 MPa, respectively; the elongation decreases rapidly at first and then remains stable with the increase of solid solution temperature, decreasing from 13.4% at 450 ℃ to 10.7%-10.4% at 500-550 ℃.
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