高温结构弛豫对非晶复合材料力学性能的影响

发布时间：2018-02-23 11:56

本文关键词： 高温结构弛豫力学性能显微结构大块金属玻璃复合材料　出处：《稀有金属》2015年02期 　论文类型：期刊论文

【摘要】：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。
[Abstract]:Cu40Zr44Al8Ag8 amorphous composites were prepared by copper mould suction casting method. The mechanical properties of the samples before and after annealing were tested by uniaxial compression test after annealing at different time (5101015202540406085min) at the glass transition temperature (TG). The microstructure and fracture morphology of the samples before and after annealing were analyzed by means of X-ray diffractometer, scanning electron microscope (SEM), transmission electron microscope (TEM) and synchronous differential scanning calorimeter (DSCC). The results showed that:. The as-cast samples are mainly amorphous, A small amount of nanoscale and micron Al3Zr intermetallic compounds are dispersed in amorphous matrix. With the annealing, the size and morphology of micron crystal phase in amorphous composites do not change, these crystal phases are the source of crack formation. However, the nanocrystalline phase is increasing and the final precipitates are Al _ 3Zr _ 2O _ Cu _ 10Zr _ 7 and Ag3Al. The mechanical properties of the BMGCs are controlled by the free volume and the precipitated crystal phase in the amorphous composites. The strength and plasticity of the samples increase slowly at the early stage of annealing. After annealing for 15 min, the maximum strength is 1.77 GPA, the maximum plastic strain is 1.67, but the free volume decreases greatly, the strength and plasticity decrease rapidly. The fracture mode also changed from a single shear plane fracture to a multi-shear plane fracture, and finally brittle splitting occurred.
【作者单位】：兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室;
【基金】：国家自然科学基金项目(50961008,51061008)资助
【分类号】：TB33;TG139.8

【参考文献】