摘要
基于计算合金形成焓的改进Miedema模型和考虑纳米颗粒表面效应,研究了钛基二元纳米合金形成焓的尺寸和成分效应.计算结果表明钛基二元合金纳米颗粒的形成焓依赖颗粒尺寸,显示了明显的尺寸效应.纳米颗粒的形成焓随粒径的减小而增大,当粒径减小到某一临界尺寸时,纳米合金的形成焓由负值转变为正值,从而降低了纳米颗粒的热稳定性.当颗粒粒径小于10 nm时,纳米颗粒发生成分聚集,这种成分聚集发生的趋势取决于纳米合金的表面形成焓.
The effects of grain size and composition on the formation enthalpy of nano binary Ti-based alloy are investigated by taking the surface effect into account within the modified Miedema model.It is demonstrated that the formation enthalpy of binary Ti based alloy with nano grains is size-dependent and exhibits evident size-effects.The formation enthalpy increases with the size decrease,and its value turns from negative to positive at a critical size,which will weaken the thermal stability of the nano grains.Furthermore,the composition segregation taking place in the nano grains of the Ti based alloy is obvious when the grain size is less than 10 nm and the tendency of segregation is dependent on the surface formation enthalpy of nanoparticle.
出处
《南华大学学报（自然科学版）》
2011年第4期85-90,共6页
Journal of University of South China：Science and Technology
基金
湖南省科技厅科研基金资助项目(2009FJ3153)
