5605
The incubation period of intact surface areas is improved by the greater hardness and yield strength of the SLM specimen , which is attributable to an increased dislocation density and a smaller grain size .
 surface areas, hardness, yield strength, SLM, dislocation density, grain size
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:
 surface areas, hardness, yield strength, SLM, dislocation density, grain size