强塑性变形与热处理对Al-12.2Zn-3.3Mg-1.4Cu-0.2Zr-0.04Sr合金组织性能的调控
发布时间：2019-06-06 17:52
【摘要】：Al-Zn-Mg-Cu系超高强铝合金,由于其优异的综合性能,被广泛应用于交通运输、航空航天、兵器工业等领域。国内外众多学者也一直致力于该类合金的组织及性能研究,以满足各应用领域下不断提高的材料性能要求。本文以自主制备的挤压态超强铝合金(Al-12.18Zn-3.31Mg-1.43Cu-0.20Zr-0.0435Sr)为实验材料,通过对合金进行OM(光学显微镜)金相组织、EBSD(电子背散射衍射)、XRD(X射线衍射)分析与硬度、电导率、拉伸性能、抗腐蚀性能(晶间、剥落)测试,研究了变形工艺(轧制、等通道转角挤压(ECAP)、热压缩)、预回复退火、时效工艺对该材料组织及性能的影响,主要研究结果如下(下文中X方向为挤压态合金轴向,Y、Z方向为挤压态合金径向,Y、Z方向间夹角为90°;ECAP加工中,Y方向与ECAP剪切面平行):探索出了一套采用常规熔铸(非快速凝固)-挤压-轧制(沿X方向)工艺,结合后续热处理(预回复、固溶、T7X-2(121℃×5h+133℃×16h)时效),制备抗拉强度达809MPa,且具有良好抗腐蚀(晶间、剥落)性能超强铝合金的方法。本文所研究合金经轧制-预回复-固溶-T7X-2时效处理后,Z方向硬度达到了251.6HV,晶间、剥落腐蚀等级分别为四级和EB级;X方向抗拉强度达到了809.2MPa,断裂延伸率为5.8%。预回复退火处理提升了轧制态合金的抗拉强度,对合金的抗腐蚀性能、硬度、电导率没有明显影响。合金的拉伸性能测试和EBSD组织分析结果表明合金的各向异性较小。本文所研究轧制态合金在T6(121℃×24h)与T7X-2时效下,抗晶间腐蚀性能相差不大,T7X-1(121℃×5h+153℃×16h)时效下,合金的抗晶间腐蚀性能最佳;T6、T7X-1时效下,合金的抗剥落腐蚀性能无明显差异,较T7X-2时效下更优。探索出了一套采用常规熔铸(非快速凝固)-挤压-ECAP(沿X方向)-热压缩工艺,结合后续热处理(固溶、T6时效),制备抗拉强度达763MPa,且具有优异抗腐蚀(晶间、剥落)性能超强铝合金的方法。本文所研究合金经ECAP-Z向热压缩-固溶-T6时效处理后,X、Y、Z方向硬度均超过240HV,晶间、剥落腐蚀等级分别为三级和EA级;X方向抗拉强度达到了763.6MPa,断裂延伸率为5.0%。本文所研究合金ECAP加工后的两种压缩方向(Z、Y),对合金的硬度、电导率、抗腐蚀性能均无明显影响。合金的抗腐蚀(晶间、剥落)性能测试和硬度测试结果表明合金的各向异性较小。Y向压缩对合金的晶粒细化效果更显著,合金经ECAP-Y向热压缩-固溶处理后,X方向10μm以下晶粒所占百分比为78.1%,而沿Z向压缩时,这一比例仅为55.2%。这是因为Y向压缩时,合金的变形方向与ECAP剪切面近似呈90°,变形更剧烈。探索出了一套采用常规熔铸(非快速凝固)-挤压-C方式两道次ECAP(沿X方向)-热压缩工艺,结合后续热处理(预回复、固溶、T7X-1时效),制备抗拉强度达778MPa,且具有优异抗腐蚀(晶间、剥落)性能超强铝合金的方法。本文所研究合金经C方式两道次ECAP-Z向热压缩-预回复-固溶-T7X-1时效处理后,X、Y、Z方向硬度均超过225HV,晶间、剥落腐蚀等级分别为三级和P级;X方向抗拉强度达到了778.4MPa,断裂延伸率6.67%。本文所研究合金C方式两道次ECAP加工后的两种压缩方向(Z、Y),对合金的电导率、抗腐蚀性能均无明显影响;对合金的硬度有一定影响。本文所研究合金经C方式两道次ECAP-热压缩-预回复-固溶处理后,相较T6时效,T7X-1时效下的抗晶间、剥落腐蚀性能更优。合金的抗腐蚀(晶间、剥落)性能测试和硬度测试结果表明合金的各向异性较小。
[Abstract]:Al-Zn-Mg-Cu is an ultra-high strength aluminum alloy, and is widely used in the fields of transportation, aerospace, and military industry and the like due to its excellent comprehensive performance. Many scholars at home and abroad have been working on the microstructure and performance of this kind of alloy, so as to meet the increasing material performance requirements under various application fields. In this paper, the self-prepared extruded super aluminum alloy (Al-12.18Zn-3.31Mg-1.43Cu-0.20Zr-0.0435Sr) is used as an experimental material, and the alloy is subjected to OM (optical microscope) metallographic structure, EBSD (electron backscatter diffraction), XRD (X-ray diffraction) analysis and hardness, electrical conductivity, tensile property and corrosion resistance (intergranular, The effect of deformation process (rolling, equal channel angular pressing (ECAP), thermal compression), pre-recovery annealing and aging process on the microstructure and properties of the material was studied. The main results are as follows (X direction is the axial direction of the extruded alloy, Y, in that Z direction, the included angle between the radial, Y and Z directions of the extruded alloy is 90 deg.; in the ECAP process, the Y direction is parallel to the shear plane of the ECAP): a set of conventional casting (non-rapid solidification)-extrusion-rolling (in the X direction) process is explored, and the subsequent heat treatment (pre-recovery, solid solution, T7X-2 (121 鈩，
本文编号：2494491
[Abstract]:Al-Zn-Mg-Cu is an ultra-high strength aluminum alloy, and is widely used in the fields of transportation, aerospace, and military industry and the like due to its excellent comprehensive performance. Many scholars at home and abroad have been working on the microstructure and performance of this kind of alloy, so as to meet the increasing material performance requirements under various application fields. In this paper, the self-prepared extruded super aluminum alloy (Al-12.18Zn-3.31Mg-1.43Cu-0.20Zr-0.0435Sr) is used as an experimental material, and the alloy is subjected to OM (optical microscope) metallographic structure, EBSD (electron backscatter diffraction), XRD (X-ray diffraction) analysis and hardness, electrical conductivity, tensile property and corrosion resistance (intergranular, The effect of deformation process (rolling, equal channel angular pressing (ECAP), thermal compression), pre-recovery annealing and aging process on the microstructure and properties of the material was studied. The main results are as follows (X direction is the axial direction of the extruded alloy, Y, in that Z direction, the included angle between the radial, Y and Z directions of the extruded alloy is 90 deg.; in the ECAP process, the Y direction is parallel to the shear plane of the ECAP): a set of conventional casting (non-rapid solidification)-extrusion-rolling (in the X direction) process is explored, and the subsequent heat treatment (pre-recovery, solid solution, T7X-2 (121 鈩，
本文编号：2494491
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