本文以分子動力學方法研究Ni-Al合金塊材之形狀記憶特性，觀察不同Ni含量比例與不同晶格排列對Ni-Al合金相變化的影響，並在低溫時分別施予不同應變加載至塑性變形，在進行升降溫循環，檢驗是否所有應變狀態造成的塑性變形皆可經溫度循環恢復原狀。
由模擬結果可發現，在高溫時Ni-Al合金晶格為體心立方結構，晶格大小大致相同，與Ni含量無關，在低溫時，Ni含量比例高於50%的合金晶格會變為斜長方體結構（麻田散體相），相變溫度受Ni的含量比例所影響，Ni含量越高相變溫度也越高，本研究提出一些判別方法可更有效的決定相變化的溫度區間。此外由模擬發現相同Ni組成比例及原子空間分佈下，不同晶格排列的模型皆有相同的相變溫度區間，且不同晶格排列的原子模型隨溫度的變形符合座標轉換關係。
由模擬發現，在低溫下Ni-Al合金並非施加任意加載至塑性變形皆具有形狀記憶特性，以滑移向量法輔助判斷發現唯有沿著<110>晶格方向滑移造成的塑性變形才可經溫度循環回復原狀，且計算其最大剪應力值明顯比無法回復原狀的加載來得小。

We employed molecular dynamics simulation to investigate the shape memory properties of Ni-Al alloy bulks. The effects of Ni composition ratio and the simulated crystal orientation on phase transformation were studied. At low temperature, different loading conditions were applied to the alloy bulk till plastic deformation is observed. Then, the deformed bulk went through the temperature cycle to examine whether it would restore to the original shape.
From the simulation, we found that Ni-Al is body-centered cubic structure at high temperature and transforms to martensite phase at certain temperature, except for the one with 50% Ni composition ratio. The phase transformation temperature was affected by the Ni composition ratio. We proposed certain analysis method to efficiently determine the phase transformation temperature. It was observed that different simulated crystal orientated models, which possess the same Ni composition ratio and atomic arrangement in space, would have the same phase transformation temperature. And the deformations of different crystal orientated models at various temperatures could be described using coordinate transformation relation.
For the same model under different loading conditions, it was found that not every plastic deformed model would restore to its original shape after the thermal cycle. With the assist of slip vector, only those were loaded to slip along <110> direction would exhibit shape memory behavior. For those loading which would restore original shape, the corresponding maximum shear stress was noticeably smaller than those did not restore.

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