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研究了稀土、钙元素低合金化对AZ31镁合金板材力学性能、弯曲及拉胀复合成形性能的影响.结果表明:加入0.3%RE,0.3Ca%(质量分数,下同)后,AZ31镁合金板材的晶粒较细、力学性能明显提高,300℃,4 h退火后室温抗拉强度为284 MPa、延伸率为23.2%:同时,该合金板材具有最好的弯曲及拉胀复合成形性能,随着温度的提高其成形性能进一步提高. 相似文献
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AZ31B镁合金薄板超塑性气胀成形 总被引:3,自引:0,他引:3
利用热拉伸试验、气胀成形、金相显微镜和扫描电镜,研究AZ31B镁合金薄板热拉伸性能、气胀成形性能及其组织结构.结果表明:在变形温度为425℃,应变速率为1.0×10-3~6.6×10-5s-1时,其流动应力4~12MPa,延伸率则为200%~327%,挤压+热轧,冷轧的镁合金薄板表现出良好的超塑性;在变形温度为425℃,应变速率为1.0×10-3s-1条件下AZ31B镁合金板材的超塑气胀成形性能较好,胀形件的高度可达24 mm以上,其高径比大于0.80. 相似文献
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采用摩擦加热的方法对2 mmAZ31镁合金板材进行加热,然后对其进行自冲铆接.对摩擦加热过程中板材的温度变化、板材的表面损伤、自冲铆接效果以及铆接接头的剪切和疲劳性能进行了研究.结果表明,摩擦加热可以将板材的温度迅速提高到自冲铆接所需要的温度,加热过程会对板材表面造成一定损伤,但损伤程度轻微;将镁合金板材摩擦加热至180℃以上再进行自冲铆接可以有效避免板材的开裂,消除裂纹,增加铆钉与板材之间的互锁量,因而可获得具有优良剪切及疲劳性能的自冲铆接接头.与电热板加热同类型镁合金板材的自冲铆接接头相比,摩擦加热自冲铆接接头的剪切强度及疲劳性能均有所增加,这表明摩擦加热对板材表面造成的轻微损伤对铆接接头的力学性能几乎没有影响. 相似文献
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S. Fida Hassan M. Paramsothy Z. M. Gasem F. Patel M. Gupta 《Journal of Materials Engineering and Performance》2014,23(8):2984-2991
Room-temperature tensile properties of AZ31 alloy have significantly been improved when reinforced with carbon nanotube via ingot metallurgy process. However, high-temperature (up to 250 °C) elongation-to-failure tensile test of the developed nanocomposite revealed a considerable softening in the AZ31 alloy matrix accompanied by an incredible ductility increment (up to 132%). Microstructural characterization of the fractured samples revealed that the dynamic recrystallization process has induced a complete recrystallization in the AZ31 alloy at a lower temperature (150 °C) followed by substantial grain growth at a higher temperature used in this study. Fractography on the fractured surfaces revealed that the room-temperature mixed brittle-ductile modes of fracture behavior of AZ31 alloy have transformed into a complete ductile mode of fracture at high temperature. 相似文献
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采用板材热成形试验机BCS-50AR及网格应变自动测量系统GMASystem,获得了AZ31镁合金薄板在150~250℃温度范围内的成形极限图(FLD)。分别将实验获得的FLD及软件自带的Keeler’s方程作为利用DYNAFORM模拟时的破裂判据,模拟研究了AZ31镁合金筒形件在150~250℃温度范围内的拉深过程,并将模拟结果与AZ31镁合金的等温拉深实验结果进行了比较。结果表明:FLD作为DYNAFORM模拟时的破裂判据,能更好地预测AZ31镁合金薄板成形过程中的破裂问题。 相似文献
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Jon T. Carter Paul E. Krajewski Ravi Verma 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(11):77-81
The hot blow forming of magnesium sheet offers significant opportunity for forming complex, lightweight parts for automotive
applications. This paper characterizes the elevated-temperature formability of AZ31 magnesium sheet materials and the effect
of processing conditions on the performance of these materials. In addition, magnesium sheet application development at General
Motors Corporation is reviewed. 相似文献
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采用Gleebe-1500D热模拟试验机对AZ31镁合金铸轧板和常规轧制板进行了等温拉仲试验,变形温度为150~400℃,应变速率为3X10-6~3×10-1 s-1.研究了AZ31镁合金铸轧板和常规轧制板在不同变形条件下的组织演变.结果表明,两种板低温变形后的组织主要包括被拉长和破碎的晶粒以及孪晶.随着变形温度的升高,AZ31镁合金开始发生动态再结晶.铸轧板高温低应变速率变形条件下晶界滑移引起的空洞尺寸、体积分数和密度均大于常规轧制板.再结晶晶粒尺寸和参数Z呈幂律关系. 相似文献
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P. J. Zhao Z. H. Chen C. F. Dong 《Journal of Materials Engineering and Performance》2016,25(7):2702-2710
In this study, a combined experimental-numerical investigation on the failure of AZ31 Mg alloy sheet in the warm stamping process was carried out based on modified GTN damage model which integrated Yld2000 anisotropic yield criterion. The constitutive equations of material were implemented into a VUMAT subroutine for solver ABAQUS/Explicit and applied to the formability analysis of mobile phone shell. The morphology near the crack area was observed using SEM, and the anisotropic damage evolution at various temperatures was simulated. The distributions of plastic strain, damage evolution, thickness, and fracture initiation obtained from FE simulation were analyzed. The corresponding forming limit diagrams were worked out, and the comparison with the experimental data showed a good agreement. 相似文献
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为了改善镁合金变形组织及弱化基面织构强度,提高边部的成形性能。将AZ31B镁合金板在250℃~400℃的温度下以0.5m/s的速度进行热轧试验,设置四种不同交叉轧制路径,利用扫描电镜(SEM)、电子背散射(EBSD)技术详细分析了不同轧制工艺得到的镁合金板上边裂的宏观形貌、微观结构和织构。研究结果表明:镁板边部裂纹随着温度的升高呈减小趋势,在400℃条件下通过RII轧制路径得到的镁合金板几乎没有裂纹的出现。边部裂纹与轧制方向大致为45度,且RII路径下镁板边部为“O”形态的封闭裂纹,很难向两端进一步扩展,裂纹最宽部分为129μm。经过交叉工艺轧制后晶粒明显细化,大部分晶粒已发生完全动态再结晶,小角度晶界数量减少,基面织构也从23.68最低可降为7.62。更加细小的晶粒不仅可以产生更大面积的晶界,同时弱化基面织构,明显抑制裂纹的扩展,控制边裂的生成。 相似文献
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In this work, the influence of pulse current parameters on springback and bending force of magnesium alloy during electropulse-assisted(EPA) V-bending was investigated. The experimental results showed that pulse current can effectively reduce the springback and the bending force compared to the experiments without current. The frequency has a more significant influence on bending force and springback than electric current density. Electroplastic(EP) effect begins to work when pulse current parameters reach a threshold value. To explore the mechanism of EPA V-bending, the microstructure evolution and fracture surface of the bending specimen were studied. It was found that pulse current can promote the occurrence of dynamic recrystallization(DRX) of magnesium alloy compared to traditional hot forming process. The fracture mode of AZ31B under EPA V-bending evolves from brittle fracture to ductile fracture with increasing pulse current parameters. Based on the discussion of athermal and thermal effects of EP effect, the mechanism of pulse current to promote DRX is studied and athermal effect is proved to exist. 相似文献
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通过在不同温度下单向拉伸实验,分别沿轧向、45°方向和横向对AZ31镁合金轧制板材的冲压性能进行了研究.结果表明:随着变形温度的升高,板材抗拉强度和屈服强度下降,断裂伸长率提高,应变硬化指数和塑性应变比降低.拉伸性能得到改善;温度高于200℃时,板材的冲压性能得到改善,其屈强比为0.876,应变硬化指数为0.158,塑性应变比为1.307. 相似文献