等径角轧制6016铝合金板材的组织及力学性能研究

发布时间：2018-06-16 17:54

  本文选题：6016铝合金 + 等径角轧制　； 参考：《湖南科技大学》2017年硕士论文

【摘要】：车身材料以铝代钢是乘用车减重,实现节能减排的重要途径之一。但目前车身用6×××铝合金各向异性强、成形性能差,是其现阶段大规模应用面临的主要问题之一。本文以6016铝合金为研究对象,采用等径角轧制工艺调控板材内部的织构组分和所占比例,通过弱化织构来提高铝合金的成形性能。本文运用了金相显微组织、XRD宏观织构、准静态单轴拉伸试验、杯突试验等分析测试手段。对比了等径角轧制板材与常规轧制板材组织及力学性能上的差异。重点研究了轧制路径、模具通道夹角、板材预热温度三组工艺参数对板材组织及力学性能的影响。得出以下结论:(1)通过等径角轧制可以使板材形变织构离散,弱化再结晶织构,减弱各向异性,提高板材的成形性能。与常规轧制相比,等径角轧制的RT态板材S织构的体积分数较低;T4P态板材Cube织构较弱,其延伸率、(?)值和I_E值远高于常规轧制的板材。而屈服强度和Δr值较常规轧制低,具有较好的成形性能。(2)轧制路径主要影响等径角变形时板材的累积应变程度。在二个道次轧制变形时,AA(两个道次的板法向不变)路径的板材累积应变比AB(两个道次的板法向相反)路径的板材高;其RT态板材中β取向线织构较弱;T4P态板材中Cube织构较弱,且存在少量较弱的{441}2(?)4、{210}001等织构,其成形性能更好,各向异性更小。(3)模具通道夹角主要影响等径角变形时板材的剪切应变和晶格旋转程度。在模具通道夹角为120°、135°和150°范围内,随着夹角的增大,T4P态板材的晶粒尺寸逐渐增大,厚向分布均匀性逐渐提高。而在135o条件下RT态板材的β取向线织构较弱;T4P态板材中Cube织构较弱,还存在少量的{023}100、{212}(?)4等较弱的织构,其成形性能更好,各向异性更小。(4)在20℃、210℃、420℃三个温度范围内,随着板材预热温度的升高,板材的成形性升高。420℃条件下,RT态板材发生动态再结晶,形变织构依然存在,但取向密度和体积分数非常低,此外还出现了少量向再结晶织构转变的中间态织构;T4P态板材出现了少量的P{011}112织构、Goss{110}001织构,各种织构强度较弱,没有强烈的再结晶织构,织构无序分布。T4P态板材具有良好的塑性和成形性,其δ29%、σ0.2110MPa、(?)≈0.75、Δr≈0.16。而T8X态板材具有良好的烘烤硬化性能,其σ_(0.2)210MPa、σ_b335MPa。
[Abstract]:Aluminum substitute for body material is one of the important ways for passenger car to reduce weight and achieve energy saving and emission reduction. However, at present, 6 脳 脳 脳 aluminum alloy has strong anisotropy and poor formability, which is one of the main problems in large-scale application. In this paper, 6016 aluminum alloy is taken as the research object. The texture composition and proportion of sheet metal are controlled by equal diameter angle rolling process, and the formability of aluminum alloy is improved by weakening the texture. In this paper, metallographic microstructure and XRD macroscopic texture, quasi static uniaxial tensile test and cupping test were used. The structure and mechanical properties of equal-diameter angle rolling plate and conventional rolling plate were compared. The effects of rolling path, die channel angle and plate preheating temperature on the microstructure and mechanical properties of the sheet were studied. The following conclusion is drawn: (1) the deformation texture of the sheet metal can be dispersed by equal path angle rolling, the recrystallization texture can be weakened, the anisotropy can be weakened, and the formability of the sheet can be improved. Compared with conventional rolling, the volume fraction of S texture of RT sheet rolled at equal diameter angle is lower than that of T4P sheet, and its elongation is lower than that of conventional rolling. The value and Ike value of the plate are much higher than that of the conventional rolled plate. However, the yield strength and 螖 r value are lower than those of conventional rolling, and the rolling path has better formability. The cumulative strain of A / A (two pass plate normal invariant) paths is higher than that of AB (two pass normal opposite) paths, and the 尾 -orientation line texture of RT sheet is weaker than that of Cube texture in T4P sheet. Moreover, there are a few weak {441} 2 + 4 and {210} 001 textures, which have better formability and lower anisotropy. The channel angle of the die mainly influences the shear strain and the lattice rotation degree of the plate when the equal diameter angle is deformed. In the range of 120 掳angle 135 掳and 150 掳of die channel angle, the grain size of T4P sheet increases with the increase of the angle, and the uniformity of thick distribution increases gradually. Under 135o condition, the 尾 -orientation line texture of RT sheet is weaker than that of T4P sheet, and there are a few weak textures such as {023} 100, {212} T4P and so on. The formability of RT sheet is better, and the anisotropy is smaller in the temperature range of 20 鈩，

本文编号：2027601