這項研究的目的是研究通過ECAP和HEBM處理AZ61-鎂合金的儲氫性能。 SiC和Ni被用作為調節性能的添加劑。ECAP製程是已經被開發並應用於材料加工之塑性變形技術之一。球磨是廣泛運用於機械研磨的另一種方法，但要處理的材料量較少，因此缺乏擴大使用規模的潛力。而此研究的目的特別是採用上述兩種方法加工後AZ61-鎂合金的微觀結構演變，及其與儲氫性能的關係。在這項研究中並探討了添加劑的作用。
通過光學顯微鏡，結合掃描電子顯微鏡(SEM)的能量色散X-Ray和X-Ray衍射方法，從結果發現，鑄態樣品包含更多第二相，在均質化熱處理之後，第二相溶解在金屬基質中。顯微組織顯示，SiC / AZ61-鎂合金的主要第二相為β-Mg17Al12，Mg2Si和SiC。對於含鎳的樣品，其他相被確定為Mg2Ni和Al3Ni。當ECAP通過量增加時，可以發現β-Mg17Al12的量增加。最初的第二相之顆粒隨著通過次數增加並破碎成小顆粒狀，並均勻地分佈在金屬基質中。ECAP之技術被發現可以減小晶粒尺寸。顯微組織觀察顯示，經過四次通過後，拉長的亞晶粒形成了等軸晶體，這證實了四次通過後發生了動態再結晶。
發現這些微結構修飾對氫吸收和脫除具有積極作用。氫容量和動力學都隨著ECAP通過次數的增加而提高。但是由於材料的不均勻，含鎳樣品的容量略有下降。與ECAP處理的樣品相比，球磨樣品顯示出更快的動能。這部分是由於顆粒和微晶尺寸的減小以及比表面積的增加，有利於吸附動能。此現象還說明球磨會影響受表面控制和3D擴散控制的速率確定因素。四次通過的樣品具有最佳的吸收和解吸能力以及動力學。以下是最佳結果； AZ61-1％SiC（6.8wt。％），AZ61-1％SiC-1％Ni（6.4wt。％）和AZ61-1％SiC-2％Ni（6.5wt。％）。含鎳的樣品顯示出最佳的吸收和解吸速率（分別為0.33wt。％min-1和1.23wt。％min-1）。

The execution of this study was aimed at investigating the hydrogen storage properties of AZ61-Magnesium alloy when processed via ECAP and HEBM. SiC and Ni were used as additives for tuning the properties. ECAP is one of the severe plastic deformation techniques that has been developed and used for bulk materials processing. Ball milling is another method that has been widely used for mechanical milling but it lacks the potential for upscaling due to the small quantity of material being processed. In particular, the purpose of this master’s work was to study the microstructure evolution of AZ61-magnesium alloy and its relationship with hydrogen storage properties when processed by the two methods mentioned above. The effect of the additive was also explored in this work.
The microstructure was investigated by an optical microscope, scanning electron microscope joined with energy dispersive X-Ray, and X-Ray Diffraction methods. From the results, it was found that as-cast samples contained more second phases that were dissolved in the metal matrix after homogenization heat treatment. The microstructure showed that the major second phases are β-Mg17Al12, Mg2Si, and SiC for SiC/AZ61-magnesium alloy. For the samples with Ni, other phases were identified as Mg2Ni and Al3Ni. The quantity of β- Mg17Al12 was found to increase when ECAP passes are increased. The original second phase particles were fragmented into small particles with an increasing number of passes and became homogeneously distributed within the metal matrix. ECAP process was found to decrease the grain size. The microstructure observation showed that elongated sub-grains form equiaxed grains after four passes which confirmed that dynamic recrystallization happens after four passes.
Such microstructural modifications have been shown to have a beneficial effect on absorption and desorption of hydrogen. All the hydrogen capacity as well as the kinetics improved with a steady increase in ECAP passes. Nevertheless, sample capacity with Ni decreased marginally because of the materials disproportion. In comparison, ball milled samples displayed quicker kinetics compared to samples processed by ECAP. This is partly due to a reduction in the particle size and crystallite size and an increase in the specific surface area that favors sorption kinetics. This phenomenon also explains that ball milling affects the rate-determining factors which are controlled by the surface and influenced by 3D diffusion. The best absorption and desorption ability and kinetics were in four pass samples. The following are the best results: AZ61-1%SiC (6.8%), AZ61-1%SiC-1%Ni (6.4%) and AZ61-1%SiC-2%Ni (6.5%). Samples with Ni showed the highest absorption and desorption levels, respectively (0.33wt.% min-1and 1.23wt.%min-1).

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