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This behaviour leads to the development of compression zone , shielding the propagating crack tip which inhibits further crack propagation , successfully enhancing toughness .
 process characterization: compression zone; concept or principle: crack propagation; machanical property: toughness
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 process characterization: compression zone; concept or principle: crack propagation; machanical property: toughness