{'fraction_non_alphanumeric': 0.026357827476038338, 'fraction_numerical': 0.011182108626198083, 'mean_word_length': 4.695454545454545, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Physical Models for Cleavage Fracture at Various Temperatures

Based on a general model for cleavage fracture including three criteria: εp≥εpc for initiating a crack nucleus; σm/ σe≥Tc for preventing the nucleated crack tip from blunting; σyy≥σf for propagating the crack, the author proposes the critical events controlling cleavage at various temperatures. At a very low temperature (-196 o C), critical event is the nucleation of a crack in ferrite at the precrack tip or at a second phase particle. At a moderate low temperature (around-100 o C), the critical event moves to the propagation of a crack initiating at a carbide into the ferrite grain. With increasing temperature (-80 o C~-30 o C), the carbide crack eligible to initiate cleavage should be the one nucleated by a higher critical strain to gain increments in the flow stress and the effective shear stress by work hardening for making up the effect of lowering yield stress. At a higher temperature (-30 o C) after the crack tip is blunted to more than 60μm and a fibrous crack extends, the critical event for cleavage fracture is the propagation of a grain-sized crack. Following the change of critical events the critical values of above three criteria also change with temperature.