脉冲超声对ZL205A合金熔体微观组织和力学性能的影响

发布时间：2018-01-05 01:19

本文关键词：脉冲超声对ZL205A合金熔体微观组织和力学性能的影响　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：ZL205A合金强度高,综合性能优异,在航空航天领域应用广泛。但它铸造性能较差,易产生缩孔、缩松、偏析等缺陷。超声熔体处理技术是一种高效、无污染的技术,可有效改善合金组织与性能。相比普通的连续超声,脉冲超声在相同输出功率下具有更高的声压幅值,可能更有利于改善合金组织。因此,研究脉冲超声对ZL205A合金熔体微观组织和力学性能的影响,优化脉冲超声工艺,可为脉冲超声在铝合金熔体的应用提供理论基础和技术支撑。以ZL205A合金为研究对象,分析脉冲超声功率、脉冲超声频率、施振时间对ZL205A合金熔体微观组织和力学性能的影响,探讨了脉冲超声作用下铝合金的凝固机理。结果表明,脉冲超声对ZL205A合金熔体微观组织和力学性能影响显著。随着脉冲超声功率、脉冲超声频率、施振时间的增加,ZL205A合金的组织先变细后变粗,合金的晶粒尺寸先减小后增大;随着脉冲超声功率、脉冲超声频率、施振时间的增加,ZL205A合金的抗拉强度和延伸率均先增大后减小。ZL205A合金在脉冲超声作用下的最佳工艺参数为脉冲超声功率1200W、脉冲超声频率1.67HZ、施振时间120s。在最佳脉冲超声工艺下,ZL205A合金的晶粒尺寸为182.43μm,抗拉强度和延伸率分别为385.4Mpa、3.1%。采用EDS测量不同脉冲超声工艺参数下ZL205A合金的Cu元素含量,探讨脉冲超声对ZL205A合金Cu元素微观偏析的影响。结果表明,脉冲超声功率与施振时间对ZL205A合金Cu元素微观偏析影响显著,脉冲超声频率影响较小。Cu元素的成分曲线在脉冲超声的作用下升高,Cu元素的有效分配系数ek得到增大,脉冲超声作用改善了Cu元素在铝合金中的分布。研究结果为脉冲超声在铝合金熔体中的应用奠定理论和技术基础,具有重要的理论和现实意义。
[Abstract]:ZL205A alloy has high strength and excellent comprehensive properties. It is widely used in aerospace field, but its casting performance is poor, and it is easy to produce shrinkage hole, shrinkage porosity, segregation and other defects. Ultrasonic melt processing technology is a kind of high efficiency. The pollution-free technology can effectively improve the microstructure and properties of the alloy. Compared with the conventional continuous ultrasound, the pulsed ultrasound has a higher amplitude of sound pressure at the same output power, which may be more conducive to improving the microstructure of the alloy. The effects of pulsed ultrasound on the microstructure and mechanical properties of ZL205A alloy melt were studied and the pulse ultrasonic technology was optimized. It can provide the theoretical basis and technical support for the application of pulsed ultrasonic in aluminum alloy melt. Taking ZL205A alloy as the research object, the power of pulsed ultrasound and the frequency of pulsed ultrasonic are analyzed. The effect of vibration time on the microstructure and mechanical properties of ZL205A alloy melt was studied. The solidification mechanism of aluminum alloy under pulsed ultrasound was discussed. The effect of pulsed ultrasound on the microstructure and mechanical properties of ZL205A alloy melt was significant. With the increase of pulsed ultrasonic power, pulse ultrasonic frequency and vibration time. The microstructure of ZL205A alloy firstly becomes fine and then coarser, and the grain size of the alloy decreases first and then increases. With the increase of pulse ultrasonic power, pulse ultrasonic frequency and vibration time. The tensile strength and elongation of ZL205A alloy increased first and then decreased. The optimum technological parameters of the alloy under the action of pulsed ultrasound was 1200W of pulsed ultrasonic power. The pulse ultrasonic frequency is 1.67 HZ, the vibration time is 120 s. The grain size of ZL205A alloy is 182.43 渭 m under the optimum pulse ultrasonic technology. The tensile strength and elongation were 385.4 Mpa-3.1.The Cu content of ZL205A alloy was measured by EDS. The effect of pulsed ultrasound on the microsegregation of Cu element in ZL205A alloy was investigated. The results showed that the influence of pulsed ultrasonic power and vibration time on the microsegregation of Cu element in ZL205A alloy was significant. The effect of pulse ultrasonic frequency on the component curve of element Cu is small. The effective partition coefficient ek of Cu element is increased under the action of pulsed ultrasound. The distribution of Cu element in aluminum alloy was improved by pulsed ultrasound. The results laid a theoretical and technical foundation for the application of pulsed ultrasonic in aluminum alloy melt and had important theoretical and practical significance.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG663;TG146.21

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