6920
The improved ferromagnetism following HIP + HT was due to several combined effects , including stress relief , consolidation of gas pores , recrystallisation , and grain growth .
 ferromagnetism, HIP, stress, consolidation, gas, grain growth
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:
 ferromagnetism, HIP, stress, consolidation, gas, grain growth