Influence of Dislocation Substructure on Size-Dependent Strength of High-Purity Aluminum Single-Crystal Micropillars

In order to understand the influence of dislocation substructures on size-dependent strength (smaller is stronger) micron-sized metals, we have fabricated single-crystal cylindrical micropillars with various diameters approximately ranging from 1 10 μm, which were prepared surface fully annealed sample and subsequently cold-rolled samples high-purity aluminum (Al). The exhibited a size dependence resolved shear stress required for slip. (τi) normalized by modulus (G) specimen diameter (d) Burgers vector (b) followed correlation τi/G=0.33(d/b)−0.63. was reduced cold-rolling, resulting in lower power-law exponents (0.26~0.31) specimens. fine introduced cold-rolling could be associated strength, can rationalized using stochastic model source length an assumption homogenously distributed dislocations existing experimental micropillars. inhomogeneous substructure cell sizes would contribute variation measured depending location, likely due probability exiting walls (local density) Al samples.