The invention discloses a 7, 000-series
alloy material for automobile bumpers. The 7, 000-series
alloy material for the automobile bumpers is characterized in that the aluminum
alloy comprises the alloy ingredients of Zn, Mg, Cu, Zr, Ti, Sn, Mn, Ag, Co, Sc, Yb, B, Cr4 and the balance aluminum and unavoidable impurities, wherein the ratio of Mg to Zn ranges from 0.17 to 0.19, the ratio of Cu to Mgranges from 0.43 to 0.53, the ratio of Cu to Ti ranges from 1.5 to 1.8, the content of one single
impurity is smaller than or equal to 0.005%, the total content of the impurities is smaller than or equal to 0.1%, the average grain
diameter of aluminum alloy grains ranges from 20 microns to 40 microns. When the alloy is observed through SEM and TEM, the area percentage of the strengthening phase MgZn2 ranges from 1% to 1.6% while the
average size of the MgZn2 ranges from 50 nanometers to 60 nanometers, the area percentage of the strengthening phase Mg2Sn ranges from 0.3% to 0.6% while the
average size of the Mg2Sn ranges from 30 nanometers to 50 nanometers, the area percentage of the strengthening phase Al6Mn ranges from 0.3% to 0.4% while the
average size of the Al6Mn ranges from 20 nanometers to 30 nanometers, the area percentage of the strengthening phase Al3Ti ranges from 0.5% to 0.8% while the average size of the Al3Ti ranges from 20 nanometers to 30 nanometers, the yield strengthranges from 580 MPa to 650 Mpa, the tensile strength ranges from 670 MPa to 720 MPa, and the elongation ranges from 18% to 23%.