Quality-Screening and Interpretation of V-Notched Charpy Data with Fractography: A Supplementary Screening Workflow for Polyolefin Blends

Charpy impact datasets for heterogeneous or partially miscible polyolefin blends often show large bar-to-bar scatter because the measured absorbed energy can mix multiple fracture events rather than a single notch-root–dominated crack front. This work introduces a supplementary, fractography-forward screening workflow for ISO 179-1 V-notched Charpy datasets: an atlas of fractographs and a failure-decision process to support comparability (poolability). Each case is assigned a five-flag ‘failure card’ (M, T, S, B, L) based on region-resolved fractographic criteria (notch-root, striker-facing surface, and mid-thickness). Five binary flags capture high-information deviations from single-front, notch-driven fracture: multiple notch-root fronts (M), blunting with arrest/branching (T), striker-side initiation (S), mid-thickness detours around a heterogeneity consistent with flow-history traces (B), and bulk–shear-lip separation (L). The workflow is demonstrated on 19 V-notched Charpy cases from an LLDPE/PP-based blends imaged under matched acquisition conditions. Screening separates datasets that can be pooled for comparative impact statistics from those that should be interpreted as non-poolable fracture events, and it reveals which fracture signatures co-occur and most strongly associate with high absorbed energy. The result is a practical “screen-then-analyze” protocol that improves data usability while preserving mechanistic interpretation and prevention guidance for recycled and compositionally uncertain polyolefin streams.