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Materials machine learning has achieved remarkable success in building accurate predictive models for properties such as formation energy, band gap, and mechanical strength. Yet the ultimate purpose of the field is not prediction but design: the discovery of new materials that deliver target properties under real-world constraints. This perspective argues that the community must shift from prediction-centric to optimization-centric workflows. Prediction-centric approaches focus on minimizing mean absolute error on randomly held-out test sets, while optimization-centric workflows aim to maximize (or minimize) a target property value within practical budgets, constraints, and sequential decision-making. These are fundamentally different objectives that demand different methods, evaluation metrics, and research priorities. A prediction-centric model may achieve low error on interpolation tasks yet fail catastrophically when asked to guide the search for extreme or out-of-distribution materials. In contrast, optimization-centric workflows treat the machine-learning model as a surrogate within an iterative loop that actively selects the next experiment or simulation. Four core principles underpin this shift: explicit goal specification that includes both the objective and all relevant constraints; robust constraint handling that distinguishes hard feasibility requirements from soft trade-offs; uncertainty awareness, where every prediction is accompanied by well-calibrated uncertainty estimates essential for balancing exploration and exploitation; and closed-loop integration that connects the model directly to automated or high-throughput experimentation and simulation. Adopting these principles will require new evaluation protocols that measure the best material discovered, sample efficiency, regret, constraint satisfaction, and extrapolation distance rather than isolated accuracy metrics. The implications extend to model development, benchmark design, journal standards, and funding priorities. Only by embracing optimization-centric workflows can materials machine learning fulfill its promise of accelerating discovery and delivering materials that solve pressing societal challenges.

Multi-fidelity learning has been positioned as a transformative tool for high-throughput materials screening, offering the ability to fuse inexpensive low-fidelity data—generated from classical force fields, tight-binding models, or CALPHAD thermodynamics—with costly high-fidelity calculations such as density functional theory (DFT). The central premise is straightforward: surrogate models can learn systematic discrepancies between fidelity levels, delivering near-DFT accuracy at a fraction of the computational expense and thereby enabling the rapid exploration of vast compositional and structural spaces that would otherwise remain inaccessible. A substantial body of work in journals including npj Computational Materials, Machine Learning: Science and Technology, Digital Discovery, Journal of Chemical Theory and Computation, Journal of Chemical Physics, and Nature Machine Intelligence has explored this paradigm through linear corrections, Gaussian process discrepancy modeling, neural network transfer learning, multi-fidelity Bayesian optimization, ensemble approaches, and hierarchical correction chains. Yet the promises remain largely unfulfilled. Despite hundreds of reported case studies, the literature reveals few, if any, experimentally validated novel materials discovered solely through multi-fidelity acceleration. Efficiency gains rarely exceed 2–5× in realistic workflows, uncertainty estimates are frequently miscalibrated outside training domains, and extrapolation to chemically distinct regions consistently collapses to the accuracy of the underlying low-fidelity baseline. Overclaims regarding order-of-magnitude cost reductions, guaranteed high-fidelity fidelity, and accelerated discovery have not materialized in practice. This review provides the first systematic synthesis of the 34 peer-reviewed publications that directly address multi-fidelity surrogate strategies in materials screening. It categorizes surrogate architectures, contrasts theoretical assumptions with empirical performance, inventories six recurring broken promises, and distills actionable lessons from the collective evidence. By foregrounding the persistent gaps between theory and application—non-stationary bias, limited transferability, and evaluation practices that favor interpolation over genuine discovery—this work offers a sober roadmap for future research in computational and data-driven materials engineering. The field must move beyond optimistic benchmarks toward honest reporting of real-world discovery metrics if multi-fidelity learning is to fulfill even a modest fraction of its original vision.

Materials discovery remains painfully slow. Traditional human-driven experimentation, followed by offline machine-learning analysis, requires weeks or months per iteration and leaves vast regions of chemical space unexplored. This position paper argues that autonomous laboratories equipped with real-time ML feedback loops represent not an incremental improvement but a necessary paradigm shift for the future of materials engineering. In these systems, robotic platforms handle synthesis and characterization while ML models continuously update and steer the next experiment, closing the discovery loop in hours rather than weeks. The current paradigm relies on human-in-the-loop decision-making, batch experimentation, and post-hoc ML training. Autonomous laboratories reverse this: robots execute synthesis and characterization tasks, a real-time ML engine analyzes streaming data, and an acquisition function immediately proposes the next candidate, all without human intervention for routine decisions. Early demonstrations have already shown accelerated discovery of battery electrolytes, perovskites, and catalysts. Real-time ML feedback loops demand online learning, rigorous uncertainty quantification, rapid acquisition functions, multi-objective optimization, constraint handling, human oversight for safety, and seamless data streaming. We articulate seven foundational principles for closed-loop discovery: integration-first design, speed as a first-class constraint, uncertainty-driven exploration, graceful degradation, data provenance, modularity, and open standards. These principles address the technical, operational, and cultural barriers that still prevent widespread adoption. While challenges remain—high initial costs, instrument integration, and long-duration experiments—the community now possesses the necessary ML maturity, robotic hardware, and orchestration tools to overcome them. This position calls for coordinated investment in shared autonomous-lab infrastructure, open standards, and training programs so that closed-loop discovery becomes the default workflow across academia and industry. Only then can materials science deliver the energy, sustainability, and electronics breakthroughs society urgently needs.

Compositional design spaces in materials engineering, particularly for alloys and multi-component systems, present exceptionally high-dimensional and sparsely populated landscapes that challenge conventional discovery workflows. A typical five-element alloy system sampled at 10% concentration increments can encompass millions of possible compositions, rendering exhaustive evaluation infeasible. Active learning has emerged as an essential paradigm for navigating these spaces efficiently, yet standard implementations often fail to address the simultaneous demands of multiple conflicting objectives—such as balancing mechanical strength against ductility, electrical conductivity against thermal stability, or performance against material cost—while properly accounting for uncertainty and practical constraints. This conceptual framework introduces an uncertainty-aware active learning approach tailored specifically for compositional design spaces with multiple objectives. The framework comprises four core components: robust uncertainty quantification that distinguishes epistemic from aleatoric contributions across heterogeneous composition regions, multi-objective acquisition functions grounded in Pareto optimization to explicitly explore trade-offs, systematic constraint handling for both hard thermodynamic limits and soft economic or manufacturability requirements, and adaptive sequential sampling strategies that prioritize informative candidates under limited evaluation budgets. The key innovation lies in a Pareto-based acquisition mechanism that integrates uncertainty estimates to balance exploration of uncertain regions, exploitation of promising trade-offs, and navigation of sparse high-dimensional manifolds. By embedding these elements into a unified conceptual structure, the framework provides design principles that enable more reliable, interpretable, and scalable materials discovery. It shifts the focus from single-objective optimization to holistic decision-making under uncertainty, ensuring that active learning not only accelerates identification of high-performing compositions but also respects real-world engineering constraints inherent to multi-component systems. The proposed approach is expected to guide both computational and experimental campaigns in alloy design, high-entropy materials, and mixed ionic conductors, ultimately fostering more sustainable and high-performance materials.

Computational materials engineering has undergone a transformative shift with the integration of data-driven methodologies and artificial intelligence, enabling accelerated discovery and design of novel materials. Uncertainty quantification (UQ) plays a pivotal role in this paradigm, addressing inherent variabilities in simulations, experimental data, and model predictions to ensure reliable decision-making in materials development. This review synthesizes recent advancements in UQ methods within computational and data-driven materials engineering, focusing on probabilistic modeling, sensitivity analysis, and Bayesian inference techniques deployed across multiscale simulations and machine learning frameworks. We examine deployment contexts ranging from molecular dynamics to additive manufacturing, highlighting how UQ enhances robustness in property prediction, process optimization, and autonomous discovery systems. By integrating insights from high-impact studies the review delineates a systems-level perspective on UQ infrastructures, emphasizing their role in bridging computational predictions with experimental validation. Key challenges such as computational efficiency and data scarcity are contextualized, alongside opportunities for multimodal integration. Ultimately, this synthesis positions UQ as an essential infrastructure for advancing materials informatics toward industrial applicability, offering a forward-looking outlook on scalable, uncertainty-aware workflows in materials engineering.

Closed-loop systems have become foundational to computational and data-driven materials engineering, integrating automated experimentation, machine learning inference, and orchestration software to compress the design-make-test-analyze cycle. These pipelines rely on continuous flows of data, models, and decisions, yet the mechanisms governing the transfer of decision authority between human experts and autonomous agents remain conceptually underdeveloped. Existing infrastructures emphasize optimization and execution but offer limited interpretive frameworks for how authority is dynamically delegated across epistemic states and pipeline stages. This manuscript presents the Decision Authority Delegation Cascade (DADC) Framework, an original systems-level architecture that formalizes delegated experimentation as a structured cascade of authority transfer. The framework delineates layered pipelines—from data representation through model inference and steering logics to execution and feedback—while emphasizing infrastructure trade-offs in representation fidelity, uncertainty quantification, and delegation thresholds. Synthesizing advances in Bayesian active learning, self-driving laboratories, and orchestration platforms, the DADC Framework interprets authority transfer not as a binary handover but as a continuous, computationally steered process that modulates discovery dynamics. The framework offers interpretive insights into scalable computational ecosystems, highlighting pathways to align human epistemic oversight with autonomous operation and to mitigate bottlenecks in closed-loop materials discovery. Its application reframes infrastructure design around explicit delegation logics, with implications for the next generation of autonomous materials platforms.