Effects of Al3(Sc1-Zr ) nano-particles on microstructure and mechanical properties of friction-stir-welded Al-Mg-Mn alloys

Microstructure and mechanical properties of friction-stir-welded Al−5.50Mg−0.45Mn Al−5.50Mg− 0.45Mn−0.25Sc−0.10Zr (wt.%) alloys were investigated by tensile tests microscopy methods. The results show that the yield strength, ultimate strength elongation Al−Mg−Mn joint are (191±3) MPa, (315±1) MPa (4.8±1.9)%, respectively. corresponding values Al−Mg−Mn−Sc−Zr (288±5) (391±2) (3.4±1.0)%. has smaller grain size, lower average misorientation angle higher low-angle boundary fraction than joint. Both two joints fracture at weld nugget zone (WNZ), Al3(Sc1−xZrx) nano-particles with a mean size (9.92±2.69) nm still remain in this “weakest zone”. Theoretical calculation indicates can provide Orowan strengthening WNZ, increasing 97 MPa.