Micromechanical model for competition between intergranular and intragranular fracture in 7××× aluminum alloys
(1.Department of Materials Science and Engineering, Central South University, Changsha 410083, China
2.湖南省长沙市中南大学材料科学与工程学院
3.School of Materials Science and Engineering, Central South University, Changsha 410083, China)
2.湖南省长沙市中南大学材料科学与工程学院
3.School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The 7××× aluminum alloys having a microstructure with precipitate free zones (PFZ) nearby the grain boundary, have received a great deal of attention due to their high strength, light mass, and yet poor fracture toughness. Experimental investigation into the effect of microstructure on the ductility was well established and comprehensive in the literature. A micromechanical model using a unit cell including some voids and relevant microstructural features was created. The competition between intergranular and intragranular fracture was investigated by comparing the void growth velocity between PFZ and matrix. The effects of void aspect ratio, relative PFZ volume, orientation of PFZ on the ductility of 7××× aluminum alloys were analyzed. The results show that the model can explain the effect of microstructure on the competition between intergranular and intragranular fracture.
Key words: aluminum alloys; micromechanical model; unit cell; intergranular fracture; intragranular fracture