本研究主要是利用霍普金森高速撞擊試驗機，討論燒結密度對316L不銹鋼粉末冶金件撞擊性能的影響。實驗中，各密度試件之製程參數由田口式分析法設計；而撞擊試驗過程於25℃進行，將相對密度93%、88%及83%試件於應變速率3×103 s-1、5×103 s-1、7×103 s-1、9×103 s-1下進行衝擊試驗，再將所得數據及微觀結果(OM、SEM)進行分析，以釐清燒結密度及應變速率對動態荷載下之塑性變形行為及微觀組織的影響。並於最後引用一材料構成方程式來描述316L不銹鋼粉末冶金件於各燒結密度及應變速率條件下之塑變行為，以做為工程模擬分析之用。

　　研究結果顯示，316L不銹鋼粉末冶金件之動態機械性質受到燒結密度及應變速率的影響甚鉅。針對相同密度的試件而言，其塑流應力及應變速率敏感性係數皆隨著應變速率的增加而上升，熱活化體積及加工硬化係數則呈現相反的趨勢；而在同一應變速率下，塑流應力值及應變速率敏感性係數隨燒結密度的增加而上升，而熱活化體積及加工硬化係數則隨燒結密度的增加而下降。最後，將各實驗條件下之塑流應力值在轉換為von Mises微觀等效應力後，藉由Khan-Huang-Liang模式之構成方程式並加入理論溫升量的修正項，可以很準確的用來描述各密度之316L不銹鋼粉末冶金件於高速撞擊下之塑變行為。

　　由破壞形貌觀察，可知316L不銹鋼粉末冶金件在高速變形下，破壞的模式由絕熱剪切帶主導，材料的破壞乃由主裂縫及次裂縫之絕熱剪切帶相互結合而成；另於壓縮過程中，在試件外緣之圓周表面處亦因孔洞聚集，使材料表面延性降低而導致表面裂縫的出現。其中，材料之主裂縫分佈與應變速率有關，而試件的密度則對於材料的表面延性有直接的影響。此外，在破斷面的觀察上，可以發現主要是以韌窩組織形貌為主的延性破壞形貌，而韌窩組織的形貌亦會隨著燒結密度及應變速率條件而有所不同。

　　This study uses the split-Hopkinson pressure bar to investigate the influence of sintering density on the dynamic impact properties of Type 316L sintered stainless steel. The Taguchi method is used to design the sintering process factors such that the sintered specimens have densities ranging from 83% to 93%. Mechanical testing is performed under strain rates between 3×103 s-1 and 9×103 s-1. OM and SEM microscopy techniques are used to analyze the fracture and microstructural characteristics of the deformed specimens to determine the relationship between the mechanical and microstructural properties. The experimental results show that the sintering density, strain and strain rate all influence the mechanical properties of the Type 316L stainless steel. At a constant sintering density, the flow stress and strain rate sensitivity increase with increasing strain rate, but the activation volume and work hardening coefficient decrease. Under a constant strain rate, the flow stress and strain rate sensitivity increase with increasing sintering density, while the activation volume and work hardening coefficient decrease. Fractographic analysis reveals that the crack distribution depends strongly on the strain rate and shows that the surface ductility decreases with decreasing sintering density. The OM and SEM fracture feature observations indicate that adiabatic shear band formation is the dominant fracture mechanism. The shear bands form along the direction of maximum shear stress. Furthermore, dimple characteristics are observed on the fracture surfaces. The depth and density of the dimples are found to decrease as the strain rate is increased. Finally, applying the Khan-Huang-Liang constitutive equation with the experimentally determined specific material parameters provides accurate predictions of the flow behaviour of Type 316L sintered stainless steel under the current test conditions.

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