由於鋼鐵材料被廣泛地使用於各個領域，鐵基非晶質合金，亦可稱之為非晶質鋼材，其數十年來一直是非晶質合金材料的研究重點之一。鐵基金屬玻璃與鋯基或鈀基非晶質合金相比之下，價格低廉的特色向來是其最具吸引力之處，但可惜的是，如此的材料卻往往因為缺乏塑性而限制了其應用範疇。為了解決鐵基金屬玻璃塑性不佳的問題，本研究成功利用真空銅模傾鑄法製作出含有外添加鉭顆粒強化的鐵基非晶質複合合金。經由壓縮試驗與硬度量測，我們發現添加13vol. %鉭顆粒塊材的塑性變形量可延展至6.43%，其破裂韌性更可增加至139.4MPa m0.5，破裂應力也高達3.18GPa，而其破裂面與施力方向的夾角為38.8度，若以未添加顆粒的非晶質合金與之相比，後者不具任何的塑性表現。根據掃描式電子顯微儀觀測分析後發現，異質相顆粒於鑄造過程中發生尺寸細化的現象，而細化後之顆粒有助於阻擋微裂隙的前進，並提升複材的機械性質。但是，鉭元素的添加會於鑄造過程中形成碳化鉭，而碳化鉭高硬度與高彈性係數的特性，最終將對材料的塑性產生危害。本研究的成果有助於瞭解使用外添加鉭顆粒對鐵基非晶質基地產生的影響與強化效果。Due to the widely used of steel, Fe-based amorphous alloy, also known as amorphous steel, is being studied by many researchers. Comparing to Zr- and Pt-based amorphous alloys, the cost of Fe-based amorphous alloy is the most attracting characteristic, especially. Unfortunately, the lack of plasticity of such material limits its application severely. According to such situation, the ex-situ method is applied in this study where the Fe-based bulk metallic glass composites Fe77Mo5P9C7.5B1.5 was casted with different amount of ex-situ Ta particles addition as the reinforcing phase by tilt mold casting in argon atmosphere. These composite alloys were examined by applying compression loading and indentation so the corresponding mechanical properties were then acquired. The BMG composite with 13vol. % Ta particles possessing a fracture toughness of 139.4 MPa m0.5 can sustain a plastic strain to failure of 6.43% at compressive fracture strength as high as 3.18GPa where the angle between the compressive shear plane and loading axis is ~38.8° while zero plasticity without reinforcing phase particles being distributed. Depending on SEM observation and analysis, the heterogeneous phase particles dispersing in the matrix decreased own sizes after casting which hold better performance to stop the propagation of micro-cracks. However, the formation of tantalum carbide which processing larger hardness and elastic modulus reduced the fraction of ductile Ta phase and thus harmed the plasticity eventually. The results of this study tended to solve the problems of fast propagation of shear bands and micro-cracks in Fe-based BMGs further providing an effective solution to improve the plasticity.
