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It was discovered that several upper layers which are in austenite phase posses hardness value higher than the final bulk microstructure of thermally decomposited martensite .
 process characterization: austenite phase; machanical property: hardness; concept or principle: microstructure; material: thermally decomposited martensite
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: austenite phase; machanical property: hardness; concept or principle: microstructure; material: thermally decomposited martensite