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The present study investigates the use of Wire-Arc additive manufacturing ( WAAM ) for hybrid manufacturing of Ti-6Al-4 V aerospace components .
 concept or principle: investigates; manufacturing process: Wire-Arc additive manufacturing; manufacturing process: WAAM; concept or principle: hybrid manufacturing; material: Ti-6Al-4 V; machine or equipment: aerospace components
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: 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:
 concept or principle: investigates; manufacturing process: Wire-Arc additive manufacturing; manufacturing process: WAAM; concept or principle: hybrid manufacturing; material: Ti-6Al-4 V; machine or equipment: aerospace components