4681
The variation of the mechanical and tribological properties is primarily due to changes in phase compositions and microstructures of the SLM maraging steels .
 concept or principle: variation; application: mechanical; concept or principle: tribological properties; concept or principle: phase compositions; material: microstructures; manufacturing process: SLM; material: maraging steels
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: variation, mechanical, tribological properties, phase compositions, microstructures, SLM, maraging steels 
Answer:
 concept or principle: variation; application: mechanical; concept or principle: tribological properties; concept or principle: phase compositions; material: microstructures; manufacturing process: SLM; material: maraging steels