4593
The results show that the specificity of the microstructure affected by the DED process and pore defects , such as segregation of Al and the existence of incomplete grain boundaries , are the main causes of crack initiation .
 microstructure, DED, pore, defects, as, Al, grain boundaries
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 microstructure, DED, pore, defects, as, Al, grain boundaries