6650
It was found that the microtexture and orientation of the columnar grains are responsible for differences in the crack growth rates , and the orientation of the columnar grains also determines the extent of the difference .
 orientation, columnar grains, crack growth, orientation, columnar grains
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:
 orientation, columnar grains, crack growth, orientation, columnar grains