挤压变形及T5热处理对稀土镁合金电磁屏蔽性能的影响
发布时间：2019-02-15 17:11
【摘要】：稀土镁合金具有密度小、强度高、耐热性好等特点,在轻量化领域有广泛的应用前景。镁合金具有优良的电磁屏蔽性能,目前国内外主要对AZ系和ZK系镁合金的电磁屏蔽性能研究较多,而对稀土镁合金的研究很少。为了解挤压变形及T5热处理对稀土镁合金的电磁屏蔽性能的影响,本文在屏蔽效能测试的基础上,结合OM、SEM、EDS及XRD等材料测试手段,分析了挤压变形与时效处理过程中微观组织的演变与稀土镁合金电磁屏蔽性能变化的关系,主要结论如下:铸态Mg-13Gd-4Y-2Zn-0.5Zr镁合金能够有效地屏蔽30~1500MHz范围内的电磁波,屏蔽等级达到了优良。在30~1500MHz测试频率范围内,Mg-13Gd-4Y-2Zn-0.5Zr镁合金的电磁屏蔽效能达到了86~107dB,而7A04铝合金和2A12铝合金的电磁屏蔽效能分别为71~107dB,55~107dB。随着频率的上升,电磁波的穿透能力逐渐增强,导致电磁屏蔽性能呈下降趋势。在热挤压变形中,随变形量增加,Mg-13Gd-4Y-2Zn-0.5Zr合金的电磁屏蔽性能逐渐提高。在30~1500MHz测试频率范围内,当变形程度为80%时,其电磁屏蔽效能达到93~107dB。由于合金晶粒随变形程度增加不断细化,导致稀土镁合金内部晶界密度不断提高,电磁波在合金内部传播中发生折射和反射的几率增大,从而增大了电磁波在合金内部的吸收损耗和多重反射损耗。另外,在热挤压变形中基面织构的逐渐增强也增加了合金内部的反射损耗。对挤压态合金进行T5热处理,随着时间的延长,其电磁屏蔽性能逐渐提高,但并没有随时间而单调变化。峰时效态(225℃×24h)稀土镁合金的电磁屏蔽性能最好,在测试频率范围内达到了96~107dB。由于时效过程中析出了大量呈弥散状分布的第二相Mg5(GdY)提高了稀土镁合金的电导率,从而增加了反射损耗和吸收损耗;同时第二相Mg5(GdY)提高了合金的相界面密度,导致内部多重反射损耗增加。但是随着时间的继续延长,第二相Mg5(GdY)的明显粗化以及部分晶粒发生长大,降低了合金内部相界面密度和晶界密度,导致合金内部多重反射损耗减小。
[Abstract]:Rare earth magnesium alloys have many advantages, such as low density, high strength and good heat resistance. Magnesium alloys have excellent electromagnetic shielding properties. At present, there are many researches on electromagnetic shielding properties of AZ and ZK series magnesium alloys, but few on rare earth magnesium alloys. In order to understand the effect of extrusion deformation and T5 heat treatment on the electromagnetic shielding properties of rare earth magnesium alloys, based on the testing of shielding effectiveness, this paper combines the testing methods of OM,SEM,EDS and XRD, etc. The relationship between the evolution of microstructure during extrusion deformation and aging treatment and the electromagnetic shielding property of rare earth magnesium alloy is analyzed. The main conclusions are as follows: as-cast Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy can effectively shield electromagnetic waves in the range of 30~1500MHz. In the range of 30~1500MHz testing frequency, the electromagnetic shielding efficiency of Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy is up to 86 ~ 107dB, while that of 7A04 aluminum alloy and 2A12 aluminum alloy is 71 ~ 107dB ~ 55 ~ 107dB, respectively. With the increase of frequency, the penetration ability of electromagnetic wave increases gradually, which leads to the decrease of electromagnetic shielding performance. In hot extrusion deformation, the electromagnetic shielding property of Mg-13Gd-4Y-2Zn-0.5Zr alloy increases with the increase of deformation amount. In the range of 30~1500MHz testing frequency, when the deformation degree is 80, the electromagnetic shielding efficiency reaches 93 ~ 107dB. As the grain size increases with the increase of deformation degree, the grain boundary density of rare earth magnesium alloy increases continuously, and the probability of refraction and reflection of electromagnetic wave in the alloy is increased. Therefore, the absorption loss and multiple reflection loss of electromagnetic wave in the alloy are increased. In addition, the gradual enhancement of the basic texture during hot extrusion also increases the reflection loss in the alloy. The electromagnetic shielding property of extruded alloy increased gradually with the prolongation of time, but it did not change monotonously with time after T5 heat treatment. The peak aging state (225 鈩，
本文编号：2423550
[Abstract]:Rare earth magnesium alloys have many advantages, such as low density, high strength and good heat resistance. Magnesium alloys have excellent electromagnetic shielding properties. At present, there are many researches on electromagnetic shielding properties of AZ and ZK series magnesium alloys, but few on rare earth magnesium alloys. In order to understand the effect of extrusion deformation and T5 heat treatment on the electromagnetic shielding properties of rare earth magnesium alloys, based on the testing of shielding effectiveness, this paper combines the testing methods of OM,SEM,EDS and XRD, etc. The relationship between the evolution of microstructure during extrusion deformation and aging treatment and the electromagnetic shielding property of rare earth magnesium alloy is analyzed. The main conclusions are as follows: as-cast Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy can effectively shield electromagnetic waves in the range of 30~1500MHz. In the range of 30~1500MHz testing frequency, the electromagnetic shielding efficiency of Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy is up to 86 ~ 107dB, while that of 7A04 aluminum alloy and 2A12 aluminum alloy is 71 ~ 107dB ~ 55 ~ 107dB, respectively. With the increase of frequency, the penetration ability of electromagnetic wave increases gradually, which leads to the decrease of electromagnetic shielding performance. In hot extrusion deformation, the electromagnetic shielding property of Mg-13Gd-4Y-2Zn-0.5Zr alloy increases with the increase of deformation amount. In the range of 30~1500MHz testing frequency, when the deformation degree is 80, the electromagnetic shielding efficiency reaches 93 ~ 107dB. As the grain size increases with the increase of deformation degree, the grain boundary density of rare earth magnesium alloy increases continuously, and the probability of refraction and reflection of electromagnetic wave in the alloy is increased. Therefore, the absorption loss and multiple reflection loss of electromagnetic wave in the alloy are increased. In addition, the gradual enhancement of the basic texture during hot extrusion also increases the reflection loss in the alloy. The electromagnetic shielding property of extruded alloy increased gradually with the prolongation of time, but it did not change monotonously with time after T5 heat treatment. The peak aging state (225 鈩，
本文编号：2423550
本文链接：https://www.wllwen.com/kejilunwen/jiagonggongyi/2423550.html
