Influence of Annealing Treatments on Microstructure and Mechanical Properties of an Extruded Mg AZ31/Al 7050 Laminate

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2019,（2）
• 页码范围: 227-234
• 页数: 8页
• 语种: 英文

摘要

Mg AZ31/Al 7050 laminate was fabricated by co-extrusion directly from the as-cast Mg AZ31 and Al 7050 billets.The influence of annealing temperature and annealing time on microstructure and mechanical behavior of the extruded Mg/Al laminate was systematically studied.Results show that annealing treatments at 250 ℃ for 3 h or at 350 ℃ for 3 h do not result in an obvious grain coarsening of Mg layer and cannot remove the heterogeneous structure.Annealing does not vary texture in the Mg layer,a large fraction of <0002>//ND and a small fraction of <0002>//TD,but the intensity of component <0002>//ND weakens to some extent.Lamellar microstructure in the Al layer remains after annealing at 250 ℃ for 3 h or at 350 ℃ for 3 h.High fractions of the texture components S and cube exist in the extruded sample,and annealing treatment hardly changes their fractions.Post-annealing treatment will largely reduce yield strength of extruded plate and increase plasticity slightly.The yield strength drops from 302 MPa to 206 MPa after annealing at 250 ℃ for 3 h and to 141 MPa after annealing at 350 ℃ for 3 h.The elongation to fracture increases from 1.5％ to 5.4％ after annealing at 250 ℃ for 3 h and to 4.8％ at 350 ℃ for 3 h.The corresponding mechanism was discussed.