(中国航空制造技术研究院，北京 100024)
摘 要: 粗晶环是铝合金挤压型材内常见的组织结构，降低了组织与性能的均匀性。本文设计了一系列阶梯式热处理工艺，利用不同温度阶段的回复作用消除变形过程累积的畸变能，控制固溶后超高强Al-Zn-Mg-Cu合金挤压型材内粗晶环的尺寸。结果表明：经(250 ℃, 24 h)、(300 ℃, 24 h)、(350 ℃, 24 h)、(400 ℃, 24 h)热处理后，粗晶环平均宽度降至未经处理的1/10~1/7，同时沿厚度方向拉伸性能均匀性显著提高。本研究为优化超高强Al-Zn-Mg-Cu合金型材的组织与性能提供了可参考办法。
关键字: 超高强铝合金；Al-Zn-Mg-Cu；粗晶环；热处理；晶粒组织；力学性能
（AVIC Manufacturing Technology Institute, Beijing 100024, China）
Abstract:Coarse crystal ring is a common structure in the extruded Al alloy profiles, which reduces the homogeneity of the microstructures and properties. In this work, a series of step heat treatment processes were designed, in which the distortion energy of deformation process was eliminated by using the recovery effect at different temperature stages to control the size of the coarse-grained rings after solution treatment. The results show that the average width of the coarse-grained rings decreases from 1/10 to 1/7 of the untreated one after the heat treatment of (250 ℃, 24 h)+(300 ℃, 24 h)+(350 ℃, 24 h)+(400 ℃, 24 h), and the uniformity of mechanical properties along the thickness direction enhances significantly. This work may provide a reference method for optimizing the microstructure and properties of the ultra-high strength Al-Zn-Mg-Cu alloy profiles.
Key words: ultra-high strength alloy; Al-Zn-Mg-Cu; coarse-grained rings; heat treatment; grain structure; mechanical properties
