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A simple annealing step transformed them into the desired equilibrium constituents of ductile ferrite ( matrix ) and light and stiff TiB2 ( particles ) , with only minimal changes in particle size ( about 20–150 nm in diameter ) and distribution ( mainly on the matrix grain boundaries ) .
 simple annealing, equilibrium, ductile, particles, particle, diameter, distribution, grain boundaries
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:
 simple annealing, equilibrium, ductile, particles, particle, diameter, distribution, grain boundaries