{'fraction_non_alphanumeric': 0.019444444444444445, 'fraction_numerical': 0.0, 'mean_word_length': 5.551515151515152, '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}}
Study on Fracture Morphologies of Nickel Based P/M Superalloy

Fracture morphology analysis is an important way to understand material fracture process, find the reason of fracture and improve its performance. Nickel based powder metallurgy (P/M) superalloy is an important material which is widely used in the modern aeronautic and astronautic industry. In order to determine the fracture characteristic morpholgies and mechanisms of the P/M superalloy fractured at different conditions, the fracture surfaces of the high temperature low cycle fatigue,high cycle fatigue, high-low cycle complex fatigue, tension and creep specimens from the P/M superalloy were studied by scanning electron microscopy and stereo-microscopy. The mechanisms and influencing factors of high temperature fatigue crack initiation and propagation were emphatically analyzed, and creep and tension fracture mechanisms of the P/M superalloy were also discussed. The application of the fracture surface analysis for the fracture failure analysis of the P/M superalloy turbine disk were introduced finally.