摘要
通过直流与脉冲电沉积分别制各平均晶粒度为20~30nm,宽晶粒度分布(5-120nm)的纳米镍。在室温静拉伸应变速率范围内,直流电沉积制备的纳米镍的平均抗拉强度和平均断裂延伸率分别为1176MPa与10.6%。而由脉冲电沉积技术制备的纳米镍抗拉强度可达1500MPa之上,最高断裂延伸率可达13.3%。与电沉积获得的普通窄晶粒度分布的纳米镍相比,宽晶粒度分布的纳米镍的塑性要高出100%以上。其原因是大型晶粒内部允许位错的存在,且理论计算表明,晶内位错可通过Frank—Read源机制进行增殖。
The flawless nanocrystalline (nc) Ni with a broad grain size distribution ranging from 5 to 120 nm and an average grain size of 20-30 nm were prepared by direct current and pulse electrodeposition, respectively. In the region of room-temperature static tensile strain rates, for the nc Ni prepared by direct current electrodeposition, the average ultimate tensile strength and the average elongation to failure are 1176 MPa and 10.6%, respectively. While for the nc Ni prepared by pulse electrodeposition, the ultimate tensile strength exceeds 1500 MPa and the max elongation to failure reaches 13.3%. In contrast to the typical electrodeposited nc Ni with a narrow grain size distribution below 50 nm, the ductility is increased by more than 100% for the present nc Ni samples. This enhancement can be interpreted by the reason that dislocations can exist and multiply in the large grains by the mechanism of Frank-Read source in the plastic deformation process revealed by theoretical calculation.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2009年第12期2075-2079,共5页
Rare Metal Materials and Engineering
基金
Natural Science Foundation of Fujian Province (E0410011)
Science and Technology Key Project of Fujian Province (2006H0020)
关键词
纳米镍
力学性能
晶粒度分布
变形机制
电沉积
nanocrystalline Ni
mechanical property
grain size distribution
deformation mechanism
electrodeposition