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Casati studied the microstructure and fracture behaviour of 316L austenitic stainless steel produced by selective laser melting and discovered that severe thermal gradients and high cooling rates affects the crystal growth and orientation of grain structure after solidification .
 concept or principle: microstructure; concept or principle: fracture; material: 316L austenitic stainless steel; manufacturing process: selective laser melting; process parameter: thermal gradients; process parameter: cooling rates; machanical property: crystal growth; concept or principle: orientation; concept or principle: grain structure; concept or principle: solidification
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:
 concept or principle: microstructure; concept or principle: fracture; material: 316L austenitic stainless steel; manufacturing process: selective laser melting; process parameter: thermal gradients; process parameter: cooling rates; machanical property: crystal growth; concept or principle: orientation; concept or principle: grain structure; concept or principle: solidification