2052
The aB-printed structures were free of large-scale defects and voids , and were further characterized and compared to commercial Blackalloy 525 barstock ( B525 ) , a Co-Cr-W alloy tool of similar composition .
 defects, voids, alloy, composition
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:
 defects, voids, alloy, composition