The Preparation Of CuZr Based Amorphous Composite And Organizational Structure, Properties Research

Owing to the good amorphous formation ability, low cost, excellent mechanical properties, Cu Zr-based amorphous alloy has attracted the attention of researchers. And studies have shown that the plasticity of alloy will rise greatly if there is B2-Cu Zr phase in the alloy system, and the alloy will also show the phenomenon of strain harden. Therefore, preparing bulk amorphous alloy matrix composites in order to improve the plasticity of the amorphous alloy has become the hot spot of this field. This article based on the Cu47Zr47Al6 alloy system, the effects of the element Y on the glass forming ability were studied firstly, then the Cu-Zr-Al-Y alloy ingots that had best glass formation ability were cold rolled and added different content of Nb and Ta respectively to promote the formation of B2-Cu Zr phase. In the end, the bulk amorphous matrix composites with excellent mechanical properties were prepared.The φ2 mm specimens with nominal compositions of(Cu0.47Zr0.47Al0.06) 100-xYx(x=0, 2, 4, 6 at.%) were prepared by vacuum of copper spray casting with low pure raw materials. Through the X-ray diffraction, differential scanning calorimeter instrument, uniaxial compression, metallographic microscope, micro vicker hardness tester, the effects of Y on the glass forming ability、microstructure and mechanical properties of the alloys were studied. The results showed that in a certain amount, the addition of Y can significantly improve the glass forming ability of Cu47Zr47Al6 alloy system and prevent the eutectoid decomposition of B2-Cu Zr phase. And within the scope of this study, when the addition of Y was 4 at.%, the alloy had the best glass forming ability and reached the maximum compressive strength 1859 MPa.The(Cu0.47Zr0.47Al0.06)96Y4 alloy that had the best glass forming ability were prepared into 1.5 mm×5 mm plate samples. Then the samples were cold rolled to promoted crystallize. And the influence of deformation on mirostructure and mechanical properties were explored. The results showed that the strain rate of 6.67 % cold rolled didn’t change the kinds of crystalline phases, which were B2-Cu Zr, Cu10Zr7, Cu Zr2 and oxide impurity phases both in as-cast and after rolling samples. However, cold rolled increased the content of crystalline phase of the samples significantly. Because of the crystalline phase and residual stress, the hardness of after rolling sample increased.The φ 2 mm alloy ingots with the nominal composition of(Cu0.45Zr0.45Al0.06Y0.04)100-xNbx(x=0, 1, 2, 3 at.%) and(Cu0.45Zr0.45Al0.06Y0.04)100-xTax(x=0, 1, 2, 3 at.%) were prepared, to explore the effect of Nb and Ta on the structure and mechanical properties. The results showed that Nb can reduce the glass forming ability of the alloy system, and it can also promote the formation of B2-Cu Zr phase as the heterogeneous nucleation agent and improve the mechanical properties of the sample. Within the scope of this experiment, when the addition of Nb was 1 at.%, the sample had the most amount of B2-Cu Zr phase and the best plastic, the plastic deformation was about 0.3 %(±0.05 %); a certain addition of Ta can reduce the glass forming ability of the alloy and promote the formation of the single B2-Cu Zr phase. Within the scope of the present experiment, when the addition was 2 at.%, the volume fraction of B2-Cu Zr reached the maximum and the sample exhibited the maximum plastic deformation(about 3 %).