近年來，在生醫用骨釘及縫合鉚釘等骨科植入物中，可降解材料發展尤為重要，鎂基金屬玻璃合金相當受矚目，因為相比傳統生醫材料或是鎂合金，其具有更良好的機械性能、與人體骨骼相似的楊氏係數、良好生物相容性。金屬玻璃是非結晶結構沒有晶界，可以降低材料的分解速率，因此適合骨科植入物。 但是金屬玻璃在常溫下壓縮材料缺乏韌性，影響了後續加工與應用。本實驗選擇具有較佳玻璃形成能力的Mg66Zn29Ca5為基材，分別添加不同體積分率(5~30 vol.%)多孔鉬顆粒與Ti-6Al-4V顆粒製成鎂基非晶質複材，利用外添加顆粒方式達到散佈強化的效果，藉此提升塊狀金屬玻璃之韌性；同時也設計並製成核殼結構(Core-Shell Structure)之棒材，以提高鎂基金屬玻璃棒材之尺寸。 結果顯示經過外添加之複材，均為部分非晶態，但其抗壓強度仍遠高於一般鎂合金，添加Ti-6Al-4V顆粒之非晶複材的破裂韌性並無明顯的改善； 添加多孔鉬顆粒之非晶複材，隨著添加量增加至20 vol.%，最大破裂韌性從1.10提升至6.1 MPa‧m1/2，且最大抗壓強度亦能保持613 MPa，並隨著顆粒添加量增加上升 進一步提升壓縮應變量 ，塑性變形量約 10%。而添加多孔鉬顆粒之core-shell複材，保持良好非晶質結構及玻璃形成能力，其破裂韌性為5.66 MPa‧m1/2，最大抗壓強度亦能保持609 MPa，Coreshell結構棒材熱性質與直徑3 mm棒材表現相仿，確實能提升其非晶性及熱性質。 ;Mg-based alloys attract lots of attention as biodegradable materials. Mg-based alloys have good mechanical properties, similar Young′s modulus to human bones as well as the good biocompatibility. Mg-Zn-Ca bulk metallic glass material has no grain boundaries which can decrease the degradation rate of the implant material in comparison with Mg alloys and suitable for orthopedic implants. However, the weakness of metallic glass is brittle which limited the workability via machining. In this study, Mg66Zn29Ca5 with better glass forming ability was selected as the substrate, porous Mo particles and Ti-6Al-4V particles with different volume fractions were added to fabricate Mg-based bulk metallic composites (BMGC). The particles are added to achieve dispersion strengthening and enhance the toughness of the bulk metal glass. At the same time, a core-shell structure rod was designed and fabricated to improve the dimension of BMGC rod. The optima results occur at 3 mm Mg-Zn-Ca BMGC rods with 20 vol.% porous Mo particles, the fracture toughness increased from 1.10 to 6.1 MPa‧m1/2 and remained the maximum compressive strength of 613 MPa. Meanwhile, the ductility also increased to about 10%. Due to the limitation of cooling rate, both Mg66Zn29Ca5 BMG and BMGC rods with 4 mm in diameter present only partial amorphous status. Therefore, a novel core-shell structure rod was developed, with pure Mg rod as core and Mg66Zn29Ca5 BMG and BMGC as shell to increase the cooling rate. As a result, 4 mm core-shell BMGCs rods (added with porous Mo particles) maintains a good amorphous structure and glass forming ability. The optimum performance occurs at the 4 mm core-shell rods with 25 vol.% porous Mo particle additions, the fracture toughness increased from 1.5 to 5.66 MPa∙m1/2 and remained the maximum compressive strength of 609 MPa.
