低频电磁铸造7050铝合金的组织与性能

采用新型低频电磁铸造技术制备了7050铝合金120 mm铸锭,研究了低频电磁场对铸锭组织和性能的影响.并对比研究了常规DC铸造和低频电磁铸造铸锭挤压和热处理后的组织与性能.结果表明,低频电磁铸造显著细化晶粒组织,并使组织分布均匀,改善铸锭的铸态力学性能.固溶并时效处理后,常规DC铸锭挤压棒材抗拉强度达到676.5 MPa,延伸率达到11.2%;低频电磁铸锭挤压棒材抗拉强度略有提高,达到677.5 MPa,延伸率提高较大,达到13.2%.低频电磁铸造对7050铝合金挤压棒材最终抗拉强度影响不大,但能够显著提高延伸率.

Structure and Properties of 7050 Alloy Prepared Through Low Frequency Electromagnetic Casting Process

The φ120 mm ingots of 7050 alloy were prepared through a new process, i.e. LFEC (low frequency electromagnetic casting). Investigates how the low frequency electromagnetic field affects the structure and mechanical properties of the as-cast ingots. Then, the microstructure and mechanical properties of the ingots after extrusion and heat-treatment were studied in comparison with those prepared through DC casting. The results showed that LFEC can get grain refining and homogenize structural distribution to improve as-cast tensile strength and elongation. After solution and ageing treatments, the tensile strength/percentage elongation of extruded specimens through LFEC process and conventional DC process are 677.5 MPa/13.2% and 676.5 MPa/11.2% respectively. A conclusion is thus drawn that the LFEC process has no significant effect on final tensile strength of extruded 7050 alloy rods, but can improve their final percentage elongation.