本文選題：原位自生復合材料　切入點：Al-Er-Zr-B　出處：《鄭州大學》2017年碩士論文

【摘要】：對于提升耐熱導電鋁合金的性能,國內外多集中在利用Fe、Cu、Zr、Er等元素的固溶強化效果和時效析出相的強化效果來提升材料的耐熱性能及強度。但是由于時效析出相為次生相,熱穩(wěn)定性比較差,在較高溫度下無法很好地起到釘扎晶界以及阻礙晶粒長大的作用。所以利用這類手段繼續(xù)提升材料的耐熱性能會受到一定限制。因此,我們采用攪拌鑄造的方式制備含有ZrB_2原位復合顆粒的鋁基復合材料。通過改變Zr、B元素的含量配比及總含量,研究可能生成的Al3Zr、ZrB_2、ErB_2、AlB_2/AlB12、AlBC等相的形貌、生成原理以及對材料性能的影響。Al3Er以典型共晶結構均勻的分布于基體內部,從而提升材料的強度和耐熱性;Al3Zr主要以層疊狀和搭橋狀的結晶方式存在于基體中,從而形成板片狀、塊狀等形貌;由于Al3Zr屬于包晶反應的產物,在非平衡凝固條件下會生成嵌套結構的;部分細小Al3Zr團聚在以Al-B相為核心的Zr-B環(huán)上;大部分自生復合的ZrB_2相細小彌散的分布于基體,另有部分聚集在以Al-B相為核心的Zr-B環(huán)中。通過對材料性能的研究發(fā)現(xiàn),隨著Zr、B元素含量的上升,基體中第二相的含量逐漸提升,強度隨添加元素的上升而提升;當Zr的添加至1.5wt.%及以上時,材料的性能沒有明顯提升;經過210℃×4h時效處理后,析出相對位錯的阻礙作用達到峰值;材料的延伸率隨著微量元素含量的上升而逐漸下降。材料的導電性能隨著Zr含量的提升,材料的導電性能有所下降;與未時效的樣品進行對比,時效后的樣品導電性能均有所提升,這是因為時效過程有效降低了固溶原子對電子的散射作用,提升了材料的電導率;實驗范圍內,成分變化對時效效果影響不大。樣品在經過210℃×8h時效并1h高溫保溫后,其強度保持率是優(yōu)于經過4h時效處理后的樣品的;相比較于Zr:B1:2的系列樣品,Zr:B=1:2系列樣品能夠在更高的溫度保溫后,達到90%的強度保持率;2.0Zr-0.48B的樣品在經過210℃×8h的時效處理后,可在320℃達到90%以上的高溫強度保持率。
[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，

本文編號：1688100