Synthesis of High Strength Nano-Micro Metallic Materials by Controlling Mesoscale Structure

研究了电沉积纳米晶Ni-W合金的组织和拉伸塑性变形行为。通过控制cu衬底的表面粗糙度，制备了具有中尺度ni偏析网络结构的Ni-W合金。Ni-14~18的抗拉强度。% W合金达到约3gpa，总应变为3~ 5%，其中大塑性应变约为0.5~ 3%。这些结果表明，ni偏析的细观尺度结构对提高拉伸塑性是有效的。还观察到加工硬化。采用fib -铣削技术，在断口附近观察到局部晶粒生长。可以认为，在局部塑性变形过程中发生了局部晶粒长大，导致加工硬化符合逆Hall-Petch强化规律。

Structure and tensile plastic deformation behaviors of electrodeposited nanocrystalline Ni-W alloys have been examined. By controlling the surface roughness of the Cu-substrate, the Ni-W alloys with mesoscale Ni-segregated network structure has been prepared. Tensile strengths of the Ni-14～18 at. % W alloys were attained to about 3 GPa with the total strains of 3～5 % containing the large plastic strain of about 0.5～3 %. These results have suggested that the Ni-segregated mesoscale structure is effective for improvement of the tensile plasticity. Work hardening was also observed. By using the FIB-milling technique, local grain growth was observed near the fractured surface. It may be suggested that the local grain growth is occurred during local plastic deformation, resulting the work hardening according to the inverse Hall-Petch strengthening law.