2012/2/15 G998 The evolution of structural materials Strength-Density Early history 3000 Bc 402 ce Dereily.p [Mg/m 材料科学与工程学院 School of Materials Science and Engineering. Gegcon The evolution of structural materials Strength-Density 50 BC 01 材料科学与工程学院 10 School of Materials Science and Engineering. 52012/2/15 5 材料科学与工程学院 School of Materials Science and Engineering 9 材料科学与工程学院 School of Materials Science and Engineering 10