【作者】 罗凯；

【导师】 李文；

【作者基本信息】 湘潭大学 ， 物理电子学， 2010， 硕士

【摘要】 随着科技与工业的发展进步,具有独特原子结构的非晶态合金凭借其各方面优异的性能及很好的应用前景,受到越来越多材料学者的关注和研究。但其较强的脆性和很难大块制备这两个缺点严重的限制了它的广泛应用。本文基于开尔文探针测试技术,对经过低温退火和压缩变形的非晶合金进行电子功函数测试以及硬度测试,通过对比电子功函数与硬度的变化规律,试图从原子尺度研究非晶合金的结构及变形行为,进而为从本质上进一步理解非晶合金独特的微观结构和力学行为,克服其在制造和应用上的困难提供理论依据及指导。本文研究的主要内容如下:1.采用钨极真空电弧熔炼技术,用负压铜模吸铸法制备了Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5非晶态合金样品系,在不同时间和温度下对样品进行退火处理。通过XRD、DSC和SEM等检测技术对铸态样品进行测试分析发现玻璃转变温度（Tg）约为623K,晶化温度（Tx）约为703K,过冷液相区为80K左右,经过退火的Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5非晶合金同原始铸态非晶合金结构都没有发生晶化转变但出现了一定程度的结构弛豫。2.基于开尔文探针技术对相同温度下进行不同时间低温退火的Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5非晶样品进行电子功函数测试,结果发现随着退火时间的增大电子功函数值呈下降趋势。3.同样使用开尔文探针系统对不同温度退火后的非晶合金样品进行电子功函数测试,发现电子功函数值随着温度的升高而减小,当温度靠近玻璃转变温度（Tg）时,电子功函数值下降的幅度加大。4.测量不同温度退火后Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5非晶样品的洛氏硬度,并将结果与电子功函数值相比较,发现硬度值与电子功函数值的变换呈反比,随着退火温度的上升而增大。运用自由体积模型和结构弛豫理论对实验结果进行分析和解释。5.测量不同压缩速率下压缩变形后的Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5非晶样品的电子功函数值,发现电子功函数值随压缩速率的增加而增大,并用自由体积模型的相关理论对实验结果进行了分析和解释。更多还原

【Abstract】 Go with the development and progress of technology and industry, bulk metallic galss （BMGs） which provided with a unique atomic structure is studied by more and more material scholars by its excellent performance and good prospects. But its brittleness and the difficult to preparation limit its wide application seriously. In our studies, the electronic work function （EWF） of the amorphous alloys which treated by low temperature heat treatment and compression were tested by scanning Kelvin probe （SKP） technique. We analyzed the variety of the EWF and hardness of the BMGs with the aim of investigating their structure and mechanical behavior by a electronic scale and learn more about the unique microstructure to overcome its shortcomings in manufacturing and application. The main contents of this paper are as follows:1. Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 amorphous alloy samples were prepared by tungsten vacuum melting technique and vacuum copper mold suction casting, and heat-treated by different annealing time and temperature. After XRD, DSC and SEM tests we found that the glass transition temperature （Tg） is 623K, the crystallization temperature （Tx） is 703K and the super cooled liquid region is about 80K. And we found that the crystallization has not took place of the annealed Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 samples and there was a structural relaxation compared with the as-cast sample.2. We tested the EWF of the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 amorphous alloy samples which were treated by low temperature heat treatment for different annealing time. The results showed that the values of the EWF decreased with the increasing of the annealing time.3. We also tested the EWF of the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 amorphous alloy samples which were treated by different annealing temperatures. And the values of the EWF also decreased with increasing the annealing temperature. When the annealing temperature is closed to the glass transition temperature （Tg）, the EWF was decreasing more obviously.4. The Rockwell hardness of the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 amorphous alloy samples were tested and compared to the change of the value of EWF. It showed that the hardness and EWF values was changed in a inversely way which the hardness increased with the rise of the annealing temperature. We analyzed experimental results with the free volume model and the structural relaxation refer to the relative literatures.5. We tested the EWF of the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 amorphous alloy samples which were compressed under different compression rate. The result shows that the values of the EWF increased when the compression rate rose. And we analyzed the result with the theory of free volume model.更多还原