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通过直流与脉冲电沉积分别制备平均晶粒度为 20~30 nm,宽晶粒度分布(5~120 nm)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 1176 MPa 与 10.6%。而由脉冲电沉积技术制备的纳米镍抗拉强度可达 1500 MPa 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。
Nanocrystalline nickel with average grain size of 20-30 nm and wide grain size distribution (5-120 nm) was prepared by DC and pulse electrodeposition respectively. In the range of static tensile strain at room temperature, the average tensile strength and the average elongation at break of nano-Ni prepared by direct current deposition were 1176 MPa and 10.6% respectively. However, the tensile strength of nano-nickel prepared by pulsed electrodeposition technology can reach 1500 MPa, and the maximum elongation at break can reach 13.3%. The nano-nickel with wide grain size distribution has a plasticity higher than 100% compared with the ordinary narrow-grain size distribution nano-nickel obtained by electrodeposition. The reason for this is that dislocations are allowed inside large grains and theoretical calculations show that intragranular dislocations can be propagated through the Frank-Read source mechanism.