高压扭转工艺对7A60超强铝合金的组织及力学性能影响

发布时间：2018-01-09 02:23

本文关键词：高压扭转工艺对7A60超强铝合金的组织及力学性能影响　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

更多相关文章： 7A60铝合金 高压扭转 微观组织 性能

【摘要】：7系铝合金具有较高的比强度、良好的力学性能因而被广泛应用于航空航天领域。现在的7系铝合金研究主要集中在合金成分以及成形工艺两个领域。由于7A60超强铝合金的合金化水平已经较高,本文仅讨论大塑性变形对其性能的影响。大塑性变形工艺具有极强的细化晶粒和均匀化组织的效果。其中高压扭转工艺(HPT)作为典型的大塑性变形,具有变形均匀,变形抗力低和变形量大的优点。本文基于变形强化机制理论,采用高温下的HPT工艺对7A60铝合金T6态轧制板材料进行不同温度,不同高径比下的实验研究。通过Deform-3D模拟软件对实验过程模拟来确定实验参数和后期分析实验的取样部位。通过宏观力学性能的实验来分析HPT实验可以提高初始7A60铝合金T6态轧制板材料的性能。通过光学金相显微镜观察、XRD和EBSD分析手段对变形过程中组织的微观组织演变进行观察,进而得出HPT对7A60铝合金T6态轧制板材料的强化机制。结果表明：在HPT过程中材料的晶粒细化明显,第二相粒子均匀的分布,其宏观性能体现为极限拉伸强度提高,显微硬度增大。直径40mm的试样应变量最大,因此其宏观力学性能最佳,直径50mm的试样次之,直径30mam的试样最差。微观组织与应变量有直接关系,变形过程中随着应变量的增加,温度会逐渐升高,进而发生再结晶现象。同时由于位错的累积,有小角度晶界产生,当位错累积到一定程度后,小角度晶界将会长大在原有大角度晶界处生长为大角度晶界。随着应变的增大,晶体内部逐渐均匀,晶粒取向差逐渐减小,微观织构强度逐渐减小,方向性逐渐消除。综上所述,HPT具有细化晶粒,均匀组织,消除晶粒取向差,消除微观方向性,减小微观织构强度的作用。
[Abstract]:7 Aluminum Alloy has high specific strength, good mechanical properties and is widely used in the field of aerospace research. 7 Aluminum Alloy now mainly concentrated in the alloy composition and the forming process of two areas. The level of 7A60 super alloy due to Aluminum Alloy has been high, this paper only discusses the great influence of plastic deformation on the the performance of large plastic deformation. The grain refinement process has extremely strong and uniform organization effect. The high pressure torsion process (HPT) as a typical large plastic deformation, has advantages of uniform deformation, deformation resistance of low and large deformation. This deformation strengthening mechanism based on the theory of the HPT process under different temperature the temperature of 7A60 Aluminum Alloy T6 rolling plate materials, different ratio of height to diameter. Under the experimental research by Deform-3D software to simulate the experimental process simulation to determine the experimental parameters and the experimental analysis of the sampling period Through the macro mechanical properties experiment and experimental analysis of HPT can improve the performance of the initial 7A60 Aluminum Alloy T6 rolling plate materials. By optical metallographic microscope, the microstructure of XRD and EBSD analysis methods of tissue deformation in the process of evolution was observed, and then draw the strengthening mechanism of HPT on 7A60 Aluminum Alloy T6 rolling plate materials. The results show that the grain refinement during HPT were obvious, the distribution of second phase particles uniformly, the macroscopic properties reflect the increase of ultimate tensile strength, micro hardness increased. The maximum sample diameter 40mm strain, so the macro mechanical properties of the best time, sample diameter 50mm, diameter of the sample micro 30mam is the worst. The organization has a direct relationship with the strain, deformation as the strain increases, the temperature will gradually increase, and the recrystallization phenomenon. At the same time due to the dislocation accumulation, a small angle grain boundary When the dislocation, accumulated to a certain extent, will be small angle grain boundaries grew up in large angle grain boundaries for the growth of the original high angle grain boundaries. With the increase of strain, the crystal gradually uniform grain misorientation decreases, micro texture intensity decreases gradually, gradually eliminate direction. In summary, HPT has a homogeneous microstructure, grain refinement the elimination of grain misorientation, eliminate micro direction, reduce the micro texture intensity.

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306;TG146.21

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