轻质Al-Mg-Li合金的微观组织与力学性能

Microstructure and mechanical properties of spray deposited Al-Mg-Li Alloy

  • 摘要: 采用熔炼和热挤压制备轻质Al-5.5Mg-2.0Li-0.1Zr-0.2Sc合金,利用X射线衍射仪、差示扫描量热仪、金相显微镜、扫描电子显微镜、显微硬度计及拉伸试验机对合金的物相组成、微观组织、力学性能及断口形貌进行检测分析,研究时效工艺温度(120 ℃和160 ℃)对合金微观组织和力学性能的影响.结果表明:Al-Mg-Li合金挤压后晶粒组织呈纤维状,存在一定数量的Al3Li(δ′)和Al2MgLi(S)相;经固溶和时效处理后,再结晶晶粒尺寸变大,主要析出相为δ′相S相;160 ℃时效处理容易加速时效析出行为,导致析出相粗化,强化效果减弱;经120 ℃/20 h峰时效处理后,合金的抗拉强度、屈服强度和延伸率分别达到532 MPa、475 MPa和4.4 %.

     

    Abstract: The Al-5.5Mg-2.0Li-0.1Zr-0.2Sc alloy was produced by casting and hot extrusion process. The phase composition, microstructure, fracture morphology and mechanical properties of the alloy were analyzed by X-ray diffraction, differential scanning calorimeter, metallographic microscope, scanning electron microscopy, microhardness tester and tensile testing machine. And the effects of aging temperature (120 ℃ and 160 ℃) on the microstructure and mechanical properties of the alloy were studied. The results show that, the microstructure of as-extruded Al-Mg-Li alloys is fibrous-like. After solid solution and aging, reinforcement phase of δ′ (Al3Li) and S1 (Al2MgLi) precipitate from alloy after aging. The alloy reaches peak aging state after aging at 120 ℃/20 h, and the tensile strength, yield strength and elongation a 532 MPa, 476 MPa and 4.4 %, respectively.

     

/

返回文章
返回