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Additionally , the introduction of Co provided solid solution strengthening and precipitation hardening via dispersion of second-phase Al9Co2 with a coherent interfacial relationship with the Al matrix .
 Co, solid solution, precipitation hardening, dispersion, Al
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:
 Co, solid solution, precipitation hardening, dispersion, Al