Solidification mechanism and micromechanical properties of qua-ternary Gd55-xZrxAl23Ni22 amorphous alloy
Here,we study the solidification mechanism and micromechanical properties of Gd55-xZrxAl23Ni22(x=0,15,25,35,45,55)amorphous alloys in this work.As a result of the immiscibility gap in Zr-Gd,the liquid quaternary Gd-Zr-Al-Ni alloy occurs the metastable phase separation at a high undercooling.Only when Zr and Gd do not coexist,the liquid ternary Gd55Al23Ni22 and Zr55Al23Ni22 alloys can quickly solidify to a single amorphous phase.At an undercooling of 530 K,the liquid Zr45Gd10Al23Ni22 alloy undergoes metastable phase separation in the manner of nucleation and growth.Therefore,it results in the formation of a spherical morphology with dual amorphous phases.The liquid Gd55-xZrxAl23Ni22(x=15,25,35)alloys are separated at 189,336,and 438 K,respectively,and form the reticular structure dual amorphous phases.With the increase of the volume fraction of the amorphous AM-Zr phase,the average hardness of the amorphous alloy increases from 3.95 to 7.95 GPa,and the elastic modulus increases from 58.27 to 101.37 GPa.The wear resistance coefficient of the amorphous alloy increases from 5.2× 1010 to 3.81 × 1011 Pa,and the apparent friction coefficient decreases from 0.11 to 0.05 with the increase of Zr content.
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