Fig. 1: Hardness as a function of strain rate \(\dot{\varepsilon }=\frac{v}{h}\).

Data for pure 99.99% nickel (blue) and nickel with 20 wt.% Cu in solid solution (red). Empty symbols represent single experimental results, while solid ones indicate average values, and error bars represent the standard deviation of the hardness data. Diamonds refer to data acquired with standard instrumented indentation. Squares refer to data acquired with pendulum impact indentation. Triangles and circles indicate data generated using LIPIT by launching diamonds (modified low-rate LIPIT) and alumina particles (standard LIPIT), respectively. Source data are provided as a Source Data file.