冷却速率对Zr-Cu基非晶合金显微结构及力学性能的影响

Effect of Cooling Rate on the Microstructure and Mechanical Properties of Zr-Cu Based Bulk Metallic Glasses

采用铜模吸铸法制备了直径分别为2、4、6 mm的Zr44Cu40Al8Ag8块体非晶合金。利用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、同步示差扫描量热仪(DSC)等手段对试样的显微结构进行了分析,采用单轴压缩试验测试了试样的力学性能。实验结果表明:试样的力学性能受自由体积和析出晶体相数量影响。当冷却速率降低时,试样塑性因自由体积减少而变小,同时强度因Al3Zr析出相增多而降低。

Zr44Cu40Al8Ag8 bulk metallic glasses composites（BMGCs） with diameters of 2 mm, 4 mm and 6 mm were prepared by a copper-mold suction casting method. X-ray diffraction（XRD）, optical microscopy（OM）, electro-scanning microscope（SEM）, transmission electron microscopy（TEM） and differential scanning calorimetry（DSC） were used to analyze its microstructure. Uniaxial compression experiment was employed to detect the mechanical properties of the samples. Results show that mechanical properties of the composites are affected by the combination of free volumes and precipitates. With the cooling rate decreasing, on the one hand, free volumes in the composites are reduced, resulting in the decrease in the plasticity of the BMGCs; on the other hand, intermetallic compound Al3 Zr phase is increased, thus reducing the strength of the BMGCs.