采用喷射铜模铸造法研究了Ni和Cu含量对Zr-Al-(Ni-Cu)四元合金的非晶形成能力的影响.利用X射线衍射仪分析了铸态合金的相结构,利用差示扫描量热仪研究了非晶合金的热学性能.结果表明:Zr-Al-(Ni-Cu)四元合金的非晶形成能力远大于Zr-Al-Ni和Zr-Al-Cu三元合金的非晶形成能力.Zr65Al7.5Ni10Cu17.5合金显示最高的非晶形成能力,其非晶形成临界直径可以达到7 mm.相似元素Ni和Cu在一定比例下共存,使液态合金的熵值增加,自由能降低,从而有效提高了合金的非晶形成能力.
Glass forming ability(GFA) of Zr-Al-(Ni-Cu) alloys with different Ni and Cu element contents was studied by injection copper mold casting method.Structures of the as-cast alloys,sliced along the cross-section,were identified by X-ray diffraction(XRD).Thermal properties of the bulk metallic glasses(BMG) were analyzed by differential scanning calorimetry(DSC).Results reveal that the critical diameters for glass formation of the ternary Zr-Al-Ni and Zr-Al-Cu alloys were highly improved by the coexistence of the similar elements(elements with similar atomic sizes and chemical properties) Ni and Cu in the quaternary Zr-Al-(Ni-Cu) alloys.For the Zr65Al7.5Ni10Cu17.5 alloy,which is the best glass former in the studied alloy system,BMG rod of 7mm in diameter was successfully synthesized.It is suggested that the significant improvement of GFA is attributed to the increase in the entropy and the decrease in free energy of the Ni and Cu substituted alloy systems.