本文以分子動力學方法研究鎳鋁合金塊材之形狀記憶行為，觀察Ni含量為68%的合金在不同的晶格排列方向的情形下對於相轉變的影響，並且在低溫時施加各式的複合加載應變至塑性變形，而後在進行升降溫循環以檢驗是否任意的加載造成的塑性變形皆可經溫度循環回復原狀。
由升降溫循環模擬的結果發現到高溫時鎳鋁合金以體心立方結構(沃斯田體相)穩定存在，而在低溫狀態時，晶格以斜方晶體(麻田散體相)的狀態出現。對於Ni含量為68%的合金來說，其相轉換溫度區間不會因為內部原子分佈位置不同而改變。此外，由模擬發現因為內部原子空間分佈相同，不同晶格排列的模型皆有相同的相轉換溫度區間。
由施加複合加載的模擬發現，在低溫下鎳鋁合金並非施加任意加載至塑性變形皆具有形狀記憶的行為，以CNP參數法輔助，發現唯有施加使內部雙晶方向層在特定平面上產生移動的加載方式才能使材料透過溫度循環回復原狀。透過最大剪應力理論，發現具有形狀回復行為的模擬其最大剪應力值會低於其餘無法回復原狀的模擬值。

We employed molecular dynamics simulation to investigate the shape memory behavior of bulk Ni-Al alloy (68% Ni atom composition). The thermal processes, i.e., cooling and heating, were applied and the equilibrated Ni-Al models were observed in order to determine the phase state at various temperatures as well as the phase transformation temperature. The effects of the simulated model with different crystal orientations were also studied. At low temperature, various loading conditions, i.e., uniaxial, simple tension, biaxial, were applied incrementally to the alloy bulk till plasticity took place. Then the loadings were removed, the models were subjected to heating process to examine whether it would restore to its original shape or not. Common neighbor parameter (CNP) was adopted to investigate the atomic configurations during the simulations.
From the heating and cooling simulations, we found that the Ni-Al alloy was body-centered cubic structure (austenite phase) at high temperature, i.e., 1700K, while it was stable as monoclinic structure (martensite phase) at low temperature. Regardless Ni atomic distribution, the phase transformation temperature did not change as long as the Ni composition ratio remained the same. It was also observed that the simulated models with different crystal orientations, which possess the same Ni composition ratio and atomic arrangement in space, would have the same phase transformation temperature.
From different loading simulations, it was found that some plastically deformed models would not restore to its original shape after heating to 1700K. Combined with CNP observation, it was noticed that only those were able to force the twinning variants to move on the specific plane would exhibit shape memory behavior. For those loadings which would restore to its original shape, the corresponding maximum shear stress was clearly smaller than those that did not restore.

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