Study On Microstructure And Mechanical Properties Of Cu-Zr-based Amorphous Alloy

Cu-Zr based amorphous composite materials with high strength,high hardness and other mechanical properties in the aerospace,electronics and other fields have great potential in applications.It is important to study the effects of different components and different compositions on the microstructures and mechanical properties of different alloys.In this paper,Cu-Zr-Al alloy and Cu-Zr-Al-Y alloy were prepared by vacuum arc melting-suction casting and induction casting.The microstructure of the alloy was analyzed by X-ray diffraction(XRD).The glass forming ability of the alloy was studied by differential scanning calorimetry(DSC).The microstructure and composition were analyzed by the scanning electron microscope(SEM),transmission electron microscopy(TEM)and spectroscopy.The mechanical properties of the alloy system were tested by room temperature compression test and microhardness experiment,and the fracture morphology was analyzed by the scanning electron microscope(SEM).The study on the microstructure and mechanical properties of Cu50-0.5xZr50-0.5xAlx(x=2,4,6at.%)alloy shows that with the increase of Al content,the glass forming ability of the alloy gradually increased.When the content of Al is 6 at.%,the glass forming ability of Cu47Zr47Al6 alloy was the strongest within the scope of this study,the supercooled liquid region width was61.38 K,Trg and ? parameters were 0.5997 and 0.4077,and the liquidus temperature dropped to1168.75 K.With the decrease of cooling rate,the main precipitated phase is CuZr(B2),CuZr(B19')and CuZr(Cm)martensite.At a certain cooling rate,CuZr(B2)will transformed into CuZr martensite phase.The addition of an appropriate amount of Al can increase the compressive strength of the Cu50-0.5xZr50-0.5xAlx(x=2,4,6 at.%)alloy,especially when the amountof is 4 at.%.The fracture strength of the alloy first increases and then decreases with the increase of Al at 3mm and 5mm.When compressed at 3mm,the compressive strength of Cu48Zr48Al4 alloy has reached 2279.5MPa,and the plastic deformation was 0.68%.With the decrease of cooling rate,the microhardness of the alloy Cu50-0.5xZr50-0.5xAlx(x=2,4,6 at.%)decreased from 3mm to 7mm,and the microhardness reaches 535.2HV when x=4.The study on the microstructure and mechanical of(Cu47Zr47Al6)100-xYx(x=0.5,1,1.5,2,2.5at.%)alloy shows that adding proper amount of Y can improve the glass forming ability of the alloy,and with the increase of Y content the glass forming ability of the alloy increases at first and then decreases.When the content of Y is 2 at.%,the(Cu47Zr47Al6)98Y2 alloy has the highest amorphous forming ability,the supercooled liquid region width was 67.56 K.With the decrease of cooling rate,the microstructure of amorphous alloy is turned to: completely amorphous region?amorphous + B2-CuZr phase?amorphous + B2-CuZr phase + CuZr martensite phase.With the increase of Y content,the compressive strength of the alloy increases firstly and then decreases.When the content of Y is 2 at.%,the fracture strength of(Cu47Zr47Al6)98Y2 alloy reaches the maximum value of 1967.9MPa.With the decrease of cooling rate,the microhardness value decreased from 3mm to 7mm.When compressed at 3mm,the microhardness of(Cu47Zr47Al6)98Y2 alloy has reached 581.0HV.