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Based on the relationship between the heterogeneous grain structure and strain hardening behavior , the strength-ductility synergy mechanism of the SLMed Al-Mg-Sc-Zr alloy was discussed .
 concept or principle: heterogeneous grain structure; manufacturing process: strain hardening; concept or principle: mechanism; manufacturing process: SLMed; material: alloy
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: heterogeneous grain structure, strain hardening, mechanism, SLMed, alloy 
Answer:
 concept or principle: heterogeneous grain structure; manufacturing process: strain hardening; concept or principle: mechanism; manufacturing process: SLMed; material: alloy