Al-Er-Zr-B原位复合铝合金组织和性能的研究

发布时间：2018-03-30 23:17

  本文选题：原位自生复合材料　切入点：Al-Er-Zr-B　出处：《郑州大学》2017年硕士论文

【摘要】：对于提升耐热导电铝合金的性能,国内外多集中在利用Fe、Cu、Zr、Er等元素的固溶强化效果和时效析出相的强化效果来提升材料的耐热性能及强度。但是由于时效析出相为次生相,热稳定性比较差,在较高温度下无法很好地起到钉扎晶界以及阻碍晶粒长大的作用。所以利用这类手段继续提升材料的耐热性能会受到一定限制。因此,我们采用搅拌铸造的方式制备含有ZrB_2原位复合颗粒的铝基复合材料。通过改变Zr、B元素的含量配比及总含量,研究可能生成的Al3Zr、ZrB_2、ErB_2、AlB_2/AlB12、AlBC等相的形貌、生成原理以及对材料性能的影响。Al3Er以典型共晶结构均匀的分布于基体内部,从而提升材料的强度和耐热性;Al3Zr主要以层叠状和搭桥状的结晶方式存在于基体中,从而形成板片状、块状等形貌;由于Al3Zr属于包晶反应的产物,在非平衡凝固条件下会生成嵌套结构的;部分细小Al3Zr团聚在以Al-B相为核心的Zr-B环上;大部分自生复合的ZrB_2相细小弥散的分布于基体,另有部分聚集在以Al-B相为核心的Zr-B环中。通过对材料性能的研究发现,随着Zr、B元素含量的上升,基体中第二相的含量逐渐提升,强度随添加元素的上升而提升;当Zr的添加至1.5wt.%及以上时,材料的性能没有明显提升;经过210℃×4h时效处理后,析出相对位错的阻碍作用达到峰值;材料的延伸率随着微量元素含量的上升而逐渐下降。材料的导电性能随着Zr含量的提升,材料的导电性能有所下降;与未时效的样品进行对比,时效后的样品导电性能均有所提升,这是因为时效过程有效降低了固溶原子对电子的散射作用,提升了材料的电导率;实验范围内,成分变化对时效效果影响不大。样品在经过210℃×8h时效并1h高温保温后,其强度保持率是优于经过4h时效处理后的样品的;相比较于Zr:B1:2的系列样品,Zr:B=1:2系列样品能够在更高的温度保温后,达到90%的强度保持率;2.0Zr-0.48B的样品在经过210℃×8h的时效处理后,可在320℃达到90%以上的高温强度保持率。
[Abstract]:In order to improve the properties of heat-resistant conductive aluminum alloy, the effect of solid solution strengthening and aging precipitation phase strengthening are mainly used to improve the heat resistance and strength of the materials at home and abroad.However, due to the secondary phase and poor thermal stability, the aging precipitation can not play a role in pinning grain boundaries and hindering grain growth at higher temperatures.Therefore, the use of such means to continue to improve the heat resistance of the material will be limited.Therefore, aluminum matrix composites containing ZrB_2 in situ composite particles were prepared by agitation casting.By changing the content ratio and total content of ZrB, the morphology, formation principle and effect of Al _ 3er _ 3er _ r on the properties of Al _ 3ZrB _ 2ErB _ 2ErB _ 2 / AlB _ 2 / AlB _ (12) Al _ (BC) phases have been studied, which are distributed uniformly in the matrix with typical eutectic structure.Thus, the strength and heat resistance of the material, Al _ 3Zr, mainly exist in the matrix in the form of stacked and bridge-like crystallization, thus forming lamellar and blocky morphology. Because Al3Zr belongs to the product of peritectic reaction,Under the condition of nonequilibrium solidification, the nesting structure is formed, some fine Al3Zr agglomerates on the Zr-B ring with Al-B phase as the core, and most of the in-situ composite ZrB_2 phase is dispersed in the matrix, while the other part is clustered in the Zr-B ring with Al-B phase as the core.It is found that with the increase of ZrB content, the content of the second phase in the matrix increases gradually, and the strength increases with the increase of the added elements, but when Zr is added to 1.5wt.% or more, the properties of the materials do not improve obviously.After aging at 210 鈩，

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