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

【摘要】：對(duì)于提升耐熱導(dǎo)電鋁合金的性能,國(guó)內(nèi)外多集中在利用Fe、Cu、Zr、Er等元素的固溶強(qiáng)化效果和時(shí)效析出相的強(qiáng)化效果來(lái)提升材料的耐熱性能及強(qiáng)度。但是由于時(shí)效析出相為次生相,熱穩(wěn)定性比較差,在較高溫度下無(wú)法很好地起到釘扎晶界以及阻礙晶粒長(zhǎng)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(huì)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(fù)合顆粒的鋁基復(fù)合材料。通過(guò)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(duì)材料性能的影響。Al3Er以典型共晶結(jié)構(gòu)均勻的分布于基體內(nèi)部,從而提升材料的強(qiáng)度和耐熱性;Al3Zr主要以層疊狀和搭橋狀的結(jié)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(yīng)的產(chǎn)物,在非平衡凝固條件下會(huì)生成嵌套結(jié)構(gòu)的;部分細(xì)小Al3Zr團(tuán)聚在以Al-B相為核心的Zr-B環(huán)上;大部分自生復(fù)合的ZrB_2相細(xì)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(guò)對(duì)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(qiáng)度隨添加元素的上升而提升;當(dāng)Zr的添加至1.5wt.%及以上時(shí),材料的性能沒(méi)有明顯提升;經(jīng)過(guò)210℃×4h時(shí)效處理后,析出相對(duì)位錯(cuò)的阻礙作用達(dá)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(dǎo)電性能隨著Zr含量的提升,材料的導(dǎo)電性能有所下降;與未時(shí)效的樣品進(jìn)行對(duì)比,時(shí)效后的樣品導(dǎo)電性能均有所提升,這是因?yàn)闀r(shí)效過(guò)程有效降低了固溶原子對(duì)電子的散射作用,提升了材料的電導(dǎo)率;實(shí)驗(yàn)范圍內(nèi),成分變化對(duì)時(shí)效效果影響不大。樣品在經(jīng)過(guò)210℃×8h時(shí)效并1h高溫保溫后,其強(qiáng)度保持率是優(yōu)于經(jīng)過(guò)4h時(shí)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(dá)到90%的強(qiáng)度保持率;2.0Zr-0.48B的樣品在經(jīng)過(guò)210℃×8h的時(shí)效處理后,可在320℃達(dá)到90%以上的高溫強(qiáng)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(hào)：1688100