基于搅拌摩擦加工6016铝合金搅拌区组织与织构研究

发布时间：2018-07-01 16:51

本文选题：6016铝合金 + 搅拌摩擦加工　；参考：《重庆交通大学》2017年硕士论文

【摘要】：近年来,提高铝合金塑性为主导的先进材料技术已成为车辆轻量化发展的潮流。细化6000系铝合金晶粒对提高其塑性成形性能有重要意义。本文基于搅拌摩擦加工6016铝合金,利用金相显微镜(OM)、电子背散射衍射技术(EBSD)、X射线光谱仪(XRF)、显微硬度和万能拉伸等实验测试方法,系统研究了搅拌摩擦加工固溶和时效两种状态6016铝合金的微观组织、织构特征和力学性能,同时对比和分析不同搅拌加工工艺对铝合金微观组织、织构特征和力学性能的影响。主要结果如下:固溶态6016铝合金在搅拌头旋转速度和加工进给速度分别为800rpm和100mm/min的加工条件下能成功的使组织细化、均匀化、致密化。经过搅拌摩擦加工后,发生动态再结晶,晶粒呈等轴晶,退火后晶粒没有长大趋势,具有很好的耐热性。在搅拌中心区、冠状区、前进侧、与后退侧四个区域中,丝织构最强分布在冠状区、前进侧和后退侧区域PD001方向上,在ND方向四个区中都表现出较弱的丝织构,冠状区区域的主要织构与搅拌中心区域的主要织构相同,冠状区织构体积分数略微强于搅拌中心区域织构体积分数,前进侧区域主要织构中没有{112}111Copper织构,后退侧区域主要织构中没有{001}110Cube织构。固溶态搅拌摩擦加工后,常温下延伸率得到显著提升,合金硬度随着TD方向延伸,是先减小后增大,呈现出凹字形状图像。时效态6016铝合金在800rpm和100mm/min的加工条件下能成功的进行组织性能优化。经过搅拌摩擦加工后,发生动态再结晶,晶粒细化,呈等轴晶,晶界第二相被搅碎或者溶解在组织内。在搅拌中心区、冠状区、前进侧、与后退侧四个区域中,搅拌中心区域主要变形织构没有{236}385Brass、{123}634S织构,只有单一的{001}100Cube织构,冠状区织构体积分数略微强于搅拌中心区域织构体积分数,前进侧区域主要变形织构{124}211R、{123}634S、{025}100Brass、{236}385Brass,织构体积分数强于后退侧任一织构。时效态搅拌摩擦加工后,常温下延伸率得到提高,合金硬度随着TD方向延伸,是先增大后减小,呈现出凸字形状图像。600rpm、100mm/min,800rpm、100mm/min,1000rpm、100mm/min,1200rpm、100mm/min四组不同搅拌针旋转速度,相同加工进给速度都能成功对6016铝合金进行组织性能优化。四组工艺都能细化晶粒,晶粒尺寸大小相近,没有产生第二相,金属不受毛刺缺陷、飞边缺陷、匙孔缺陷的影响。最强丝织构产生在1000rpm、100mm/min区域TD方向335、535丝织构,最强面织构产生在600rpm、100mm/min区域ND方向(111)面织构,1200rpm、100mm/min区域主要变形织构{025}100Brass、{001}100Cube、{011}100Goss、{001}110Cube、{112}111Copper、{111}112Brass、{111}110Brass变化复杂。搅拌针旋转速度和加工进给速度800rpm、100mm/min加工条件下,能够得到最高的抗拉强度和最好的延伸率。1200rpm、100mm/min的加工条件下能成功获得高硬度。
[Abstract]:In recent years, the advanced material technology of improving aluminum alloy plasticity has become the trend of vehicle lightweight development. It is important to refine the grain of 6000 series aluminum alloy to improve its plastic forming property. In this paper, based on friction stir processing of 6016 aluminum alloy, metallographic microscope (OM), electron backscatter diffraction (EBSD) X-ray spectrometer (XRF), microhardness and universal tensile test were used. The microstructure, texture characteristics and mechanical properties of 6016 aluminum alloy with solid solution and aging in friction stir processing were systematically studied. The effects of different stirring processes on the microstructure, texture characteristics and mechanical properties of aluminum alloy were compared and analyzed. The main results are as follows: the solid solution 6016 aluminum alloy can refine, homogenize and densify the microstructure under the condition that the rotating speed of the stirring head and the machining feed rate are 800rpm and 100mm/min, respectively. After friction stir processing, dynamic recrystallization occurs, the grain is equiaxed, and the grain does not grow after annealing, so it has good heat resistance. Among the four regions of agitation center, coronal region, forward side, and receding side, the silk texture is the strongest in the coronal area, and in the forward and retrogressive region PD001, and in the ND direction, the silktexture is weaker in the four regions. The main texture of the coronal region is the same as the main texture of the stirring center. The volume fraction of the coronal texture is slightly stronger than the volume fraction of the texture in the stirring center, and there is no {112} 111 Copper texture in the main texture of the forward lateral region. There is no {001} 110 Cube texture in the main texture of the receding side. After solid solution friction stir processing, the elongation at room temperature was significantly increased, and the hardness of the alloy extended along TD direction, which decreased first and then increased, showing a concave shape image. The microstructure and properties of aged 6016 aluminum alloy can be optimized successfully under the conditions of 800rpm and 100mm/min. After friction stirring, dynamic recrystallization occurs, the grain is fine and equiaxed, the second phase of grain boundary is crushed or dissolved in the microstructure. In the four regions of agitation center region, coronal region, forward side, and receding side, the main deformation texture in the stirring center region has no {236} 385BrassS, {123} 634S texture, only a single {001} 100Cube texture, the main deformation texture in the stirring center region is not {236} 385BrassS, {123} 634S texture. The volume fraction of the coronal texture is slightly stronger than that of the stirring center, and the main deformation texture {124} 211R, {123} 634S, {025} 100 Brass, {236} 385Brass. the volume fraction of the texture is stronger than that of any texture on the receding side. After aging friction stir processing, the elongation at room temperature was increased, and the hardness of alloy increased first with TD direction, and then decreased, showing a convex shape image of .600rpmN 100mm / min ~ 100mm / min ~ 1000rpm ~ 100mm / min ~ 1200rpm / min ~ 100mm / min, four groups of four groups with different rotating speed of needle. The microstructure and properties of 6016 aluminum alloy can be optimized successfully at the same feed rate. All the four processes can refine the grain size and have no second phase. The metal is not affected by burr defect flash defect and keyhole defect. The strongest silk texture is produced in the 100mm / min TD direction of 1000rpmm-1 / min, and the strongest surface texture is produced in the 600rpmlm 100mm / min ND direction (111) plane texture. The main deformed texture {025} 100Brass, {001} 100Cube, {011} 100Goss, {001} 110Cube, {112} 111Copper, {111} 112Brassass, {111} 110Brass are complex. The highest tensile strength and the best elongation of 100 mm / min can be obtained under the conditions of rotating speed and feeding speed 800 rpm / min, and the high hardness can be obtained successfully under the condition of 100mm / min of rotation speed and feeding speed of the agitated needle, and the highest tensile strength and the best elongation of 100 mm / min can be obtained.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.21

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