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The influence of pre-deformation and heat treatment on mechanicalproperties of as-extruded ZK60 alloy was investigated.The experimentalresults indicated that the solid solution,pre-cold rolling and artificialaging treatments remarkably improved the mechanicalstrength of alloys compared with the asextruded condition.Especially,pre-cold rolling in 5% reduction combined with artificialaging at 150 ℃ for 20 h was determined as the optimum heat treatment condition,which resulted in a yield strength of 333 MPa with an increment of 87 MPa and ultimate tensile strength of 373 MPa.High density of nanoscale precipitates in α-Mg matrix observed in this sample was beneficialto enhancing the strength.The as-extruded sample showed a typicalbrittle fracture while the solution treated sample exhibited ductile-fragile failure characterized by cleavage fractures,river patterns,and tear ridges.And the sample after pre-cold rolling combined with aging presented more equiaxialdimples with a great amount of cracked particles in them.The above-mentioned observations were analyzed in terms of microstructure and possible strengthening mechanism in the extruded ZK60 alloy.
The influence of pre-deformation and heat treatment on mechanical properties of as-extruded ZK60 alloy was investigated. The experimental results indicated that the solid solution, pre-cold rolling and artificialaging treatments remarkably improved the mechanical strength of alloys compared with the asextruded condition. Especially, pre -cold rolling in 5% reduction combined with artificialaging at 150 ℃ for 20 h was determined as the optimum heat treatment condition, which resulted in a yield strength of 333 MPa with an increment of 87 MPa and ultimate tensile strength of 373 MPa. High density of nanoscale precipitates in α-Mg matrix observed in this sample was beneficial to enhance the strength.The as-extruded sample showed a typical bruittle fracture while the solution treated sample exhibits ductile-fragile failure characterized by cleavage fractures, river patterns, and tear ridges. And the sample after pre-cold rolling combined with aging presented more equiaxialdimples with a great amount of cracked particles in them. The above-mentioned observations were analyzed in terms of microstructure and possible strengthening mechanism in the extruded ZK60 alloy.