  Recent research in multi-principal element alloys (MPEAs) has increasingly
focused on the exploration and exploitation of short-range order (SRO) to
enhance material performance. However, the understanding of SRO formation and
the precise tuning of it within MPEAs remains poorly understood, limiting the
comprehension of its impact on material properties and impeding the advancement
of SRO engineering. Here, leveraging advanced additive manufacturing techniques
that produce samples with a wide range of cooling rates (up to 10^7 K/s) and an
improved quantitative electron microscopy method, we characterize SRO in three
CoCrNi-based MPEAs to unravel the role of processing route and thermal history
on SRO. Surprisingly, irrespective of the processing and thermal treatment
applied, all samples exhibit similar levels of SRO, suggesting that prevalent
SRO may form during the solidification process. Atomistic simulations of
solidification verify that local chemical ordering arises in the liquid-solid
interface (solidification front) even under the extreme cooling rate of 10^11
K/s. This phenomenon stems from the swift atomic diffusion in the supercooled
liquid, which matches or even surpasses the rate of solidification. Therefore,
SRO is an inherent characteristic of most MPEAs, insensitive to variations in
cooling rates and annealing treatments typically available in experiments.
Integrating thermal treatment with other strategies, such as mechanical
deformation and irradiation, might be more effective approaches for harnessing
SRO to achieve controlled material properties.
