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采用铜模吸铸法制备了Cu40Zr44Al8Ag8非晶复合材料(BMGCs),在玻璃转变温度(Tg)退火不同时间(5,10,15,20,25,40,60,85min)后,采用单轴压缩实验测试了试样退火前后的力学性能,并利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和同步差示扫描量热仪(DSC)等手段对退火前后试样的显微结构和断口形貌进行分析。结果发现:所制备铸态试样主要为非晶结构,非晶基体中弥散分布着少量的纳米级及微米级的Al3Zr金属间化合物。随着退火的进行,非晶复合材料中微米级晶体相的尺寸和形貌并不发生变化,这些晶体相是裂纹形成的源泉;但是纳米级晶体相不断增加,最终析出产物相为Al3Zr,Cu10Zr7和Ag3Al相。非晶复合材料中自由体积与析出晶体相共同控制着该BMGCs的力学性能。退火初期,试样的强度和塑性缓慢增长,至退火15 min时达到极值,最高强度达到1.77 GPa,最大塑性应变量达到1.67%;但是继续退火,试样内自由体积大量减少,强度和塑性均迅速下降;其断裂方式也由单一剪切面断裂转变为多剪切面断裂,最后发生脆性劈裂。
Cu40Zr44Al8Ag8 amorphous composites (BMGCs) were prepared by copper mold suction casting. After the glass transition temperature (Tg) was annealed at different times (5, 10, 15, 20, 25, 40, 60, 85min) The mechanical properties of the samples before and after annealing were experimentally tested. The samples before and after annealing were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and synchronous differential scanning calorimeter (DSC) The microstructure and fracture morphology of the sample were analyzed. The results show that the prepared as-cast samples are mainly amorphous, and a small amount of nano-scale and micron-sized Al3Zr intermetallic compounds disperse and disperse in the amorphous matrix. As annealing progresses, the size and morphology of the micron-sized crystal phase in the amorphous composite material do not change, and these crystal phases are the source of crack formation. However, the nanocrystalline phase increases continuously and the final precipitated product phase is Al3Zr, Cu10Zr7 And Ag3Al phase. The mechanical properties of BMGCs are controlled by the free volume and the precipitated crystals in the amorphous composites. At the beginning of annealing, the strength and ductility of the sample slowly increased until reaching the extreme value at 15 min after annealing. The maximum strength reached 1.77 GPa and the maximum plastic strain reached 1.67%. However, after annealing, the free volume in the sample decreased greatly and the strength and ductility All decreased rapidly. The fracture mode also changed from a single shear plane fracture to a multi-shear fracture, and finally a brittle fracture occurred.