摘要
由微米级粗晶颗粒和纳米级纳晶颗粒组成的纳米晶双峰材料不仅具有高强度,还具有较高的延性。根据Taylor强度理论和Johnson-Cook模型提出纳米晶双峰材料的一个新的本构模型,研究了晶粒尺寸和纳米裂纹对纳晶双峰材料本构及失效行为的影响,并进行了数值计算。结果表明,模型预测的结果与实验结果有很好的一致性。由计算结果可知:在纳晶双峰材料中,纳晶基体能提供高强度,粗晶能有效提高材料延性;纳米裂纹的存在不会导致破坏,反而对应变硬化起积极作用。
Bimodal nanocrystalline（BNC） materials composed of coarse grains（CG） and nanocrystalline grains（NG）, have both high strength and good ductility. In this paper, a new constitutive model was proposed by using Taylor strength theory and the Johnson-Cook modelto analyze the effect of grain size and nano-cracks on the constitutive/failure behavior of BNC materials. Numerical calculations have been carried out according to the model. It was found that the prediction result is in good agreement with experimental data. It can be concluded from the calculations that in BNC materials,（1） NC matrix can provide high strength, whereas CG can induce strain hardening to enhance its ductility,（2） the existence of nano-cracks does not lead to materials failure but a positive effect on strain hardening.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2015年第12期889-894,共6页
Chinese Journal of Materials Research
基金
国家自然科学基金51301069
河北省自然科学基金E2014502073
中央高校基本科研业务费2014MS114资助项目~~
