8594
For both materials , in situ thermal imaging and post-mortem fractography shows , respectively , rapid cool-down of the rasters during filament deposition and presence of voids between adjacent raster roads ; both of which serve to reduce fracture toughness .
 materials, in situ, imaging, fractography, filament, deposition, voids, fracture
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:
 materials, in situ, imaging, fractography, filament, deposition, voids, fracture