| 吴萍萍,张静静.镁基复合材料高温变形研究进展[J].材料导报,2018,32(17):3041-3050, 3075 |
| 镁基复合材料高温变形研究进展 |
| Advances in Hot Deformation Studies of Magnesium Matrix Composites |
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| DOI：10.11896/j.issn.1005-023X.2018.17.017 |
| 中文关键词: 镁基复合材料 高温变形 本构方程 软化机理 |
| 英文关键词: magnesium composites, hot deformation, constitutive equation, softening mechanism |
| 基金项目:航天八院基金(USCAST2013-22) |
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| 摘要点击次数: 2219 |
| 全文下载次数: 901 |
| 中文摘要: |
| 自20世纪80年代以来,不同类型(颗粒、晶须、纤维等)的增强镁基复合材料日益增多并得到了广泛的研究。镁基复合材料可设计性较强,且具备突出的力学性能与物理性能,包括低密度、高比刚度、较低的热膨胀系数、良好的阻尼性能、优异的抗震降噪能力及优良的电磁屏蔽性能等,在航空航天、军工制造、汽车电子、建筑用材及生物医用等各领域有着巨大的发展前景,被视作在先进技术领域颇具竞争力的一种轻质金属基复合材料。 然而,镁及镁合金的晶体结构为密排六方型,室温下独立的滑移系相对较少,相应地,镁及镁合金具备较差的塑性加工能力。同时,作为硬质相的增强相,与基体镁合金之间的物理化学性能相差较大,存在一定的不兼容性。增强相的添入进一步恶化了镁基复合材料的塑性加工能力,这在很大程度上限制了镁基复合材料的使用。因而,开展关于镁基复合材料在高温变形等方面的研究工作十分重要。国内外关于镁基复合材料高温变形行为方面的科研工作大部分聚焦于不同的工艺参数对高温变形行为的影响、高温变形时发生的加工硬化及动态再结晶现象、建立相应的本构模型等方面。 镁基复合材料常见的高温变形方式主要有五种,分别为超塑性变形、高温压缩、热循环变形、高温蠕变及高温二次变形。研究者们针对不同的高温变形方式开展了大量的研究工作,并取得了较为显著的研究成果。其中,高温压缩由于变形工艺相对简单而得到了更为广泛深入的研究。近年来,研究者们不仅探究了不同高温变形方式对镁基复合材料微观组织与性能的影响,还探究了应变量、温度、应变速率等变形条件对镁基复合材料高温变形行为的影响,更深入地探究了镁基复合材料在高温变形过程中的微观组织演变规律与相应的变形机制,结合数值分析构建了相应的本构模型,为镁基复合材料高温变形工艺的制定与优化提供了强有力的理论支持,有助于实现对镁基复合材料微观组织与性能的有效调控。 本文综述了镁基复合材料高温变形的不同类型,阐释了镁基复合材料高温变形的本构方程及软化机理,并展望了今后镁基复合材料在高温变形方面的发展方向。 |
| 英文摘要: |
| Various types (particle, whisker and fiber) reinforced magnesium matrix composites have been extensively studied since the early 1980s due to their excellent designability as well as outstanding mechanical and physical properties, including low density, high specific stiffness, low thermal expansion coefficient, favorable damping capability, significant shock resistance and excellent electromagnetic shielding performance. As a light metal matrix composite, magnesium matrix composites are highly competitive in advanced technology field, which possess extensive prospect in aerospace, military, automotive, electronics and other applications. Nevertheless, the plastic deformation capability of magnesium alloy is quite poor, due to close-packed hexagonal structure and limited slip system at ambient temperature. Moreover, incompatibility caused by the difference of physical and chemical properties in hard phase reinforcements and the magnesium matrix alloy would further deteriorate the plastic deformation capability of magnesium composites, which may limit the application of magnesium composites to large extent. Therefore, it is of great importance to carry out the studies on hot deformation of magnesium composites. Previous studies about hot deformation of magnesium composites at home and abroad are mainly focused on the effects of deformation parameters on the deformation behaviors, the phenomena of work hardening and dynamic recrystallization during the hot deformation process, as well as establishment of constitutive equation. Generally, there are five common hot deformation modes of magnesium composites, including superplastic deformation, hot compression, thermal cycling deformation, high temperature creep and secondary hot deformation. Plenty of studies on various hot deformation have been conducted and remarkable progress has been achieved over the years. Furthermore, thanks to its relatively simple deformation process, the hot compression of magnesium composites has attracted more attentions from researchers. In recent years, researchers have studied the influence of different hot deformation methods on microstructure and properties of magnesium composites, as well as the effect of deformation parameters including deformation strain, temperature and strain rate on hot deformation behavior of magnesium composites. In addition, the microstructure evolution and relevant deformation mechanisms of magne-sium composites during the hot deformation process have been investigated, and the corresponding constitutive equations have been established combined with numerical analysis. These research results would provide great supports for the determination and optimization of hot deformation processing of magnesium composites, and contribute to controlling the microstructure and properties of magnesium composites effectively. Different kinds of hot deformation of magnesium matrix composites are introduced. The constitutive equation as well as softening mechanism of hot deformation of magnesium matrix composites are explained in detail. Finally, the critical research directions and the remaining challenges to be addressed are summarized. |
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