One-step consolidation and precipitation hardening of an ultrafine-grained Al-Zn-Mg alloy powder by Spark Plasma Sintering

In the present work, ultrafine-grained Al-Zn-Mg alloy produced by high energy ball milling and Spark Plasma Sintering was synthesized. The Hall-Petch strengthening due to grain refinement (about 150 nm) is preserved and the Orowan's effect attributed to the presence of the hardening phase η' is obtained in a single-step during the sintering. Maximum compression stresses as high as 736 MPa and 830 MPa were reached in quasistatic and dynamic conditions respectively. Hardness was increased from 124 HV5 for a consolidated coarse grained material to 196 HV for a consolidated ultrafine-grained (UFG) material. The mechanical properties obtained in this study were all superior to the ones of the reference AA7020-T651.