Zr63.36Cu14.52Ni10.12Al12非晶合金的大塑性与尺寸效应

用铜模吸铸法制备了直径为3,4和6mm的Zr63.36Cu14.52Ni10.12Al12阶梯形圆棒试样,研究了试样尺寸大小对室温塑性和强度的影响.结果表明：φ3mm试样的压缩屈服强度σs为1740.6MPa,极限强度σmax为2030.7MPa,断裂强度σcf为1510.5MPa,塑性应变εp为20.6%,表现出比较大的塑性,存在明显的加工硬化现象;φ4mm试样塑性应变εp为2.6%,屈服强度σs为1748.5MPa,断裂强度σcf为1856.6MPa;φ6mm试样塑性应变φp为0.2%,断裂强度σcf为1221.3MPa.该合金的压缩塑性应变随着块体非晶合金直径的增大而减小,存在明显的尺寸效应,尺寸效应与非晶合金的自由体积有关,冷却速率决定非晶合金中自由体积分数,试样尺寸越小,冷却速率就越大,凝固过程形成的自由体积分数越大,大的自由体积分数促进压缩过程多重剪切带的形成从而有利于塑性的提高.

Large plasticity and size effect of Zr63.36Cu14.52Ni10.12Al12 bulk metallic glasses

Stagewise-shaped Zr63.36Cu14.52Ni10.12Al12 rod with different diameters were prepared with copper mold suction casting process.The size effects of Zr-based BMGs on plastic deformation were studied.The results show that the plastic strains（εp）,yield strength（σs）,maximum strength（？max） and facture strength（σcf） are 20.6%,1740.6 MPa,2030.7 MPa and 1510.5 MPa for φ3 mm sample,which are 2.6%,1748.5 MPa,1856.6 MPa and 1856.6 MPa for φ4 mm sample respectively.For φ6 mm sample,the plastic strains（εp） and facture strength（σcf） are 0.2% and 1221.3 MPa.The compressive plastic strain increases with the decreasing diameter of the as-cast specimens,which indicate obvious size effect.Size relavance with free volume is contained in the BMGs during the rapid solidification.The higher cooling rate is,the larger free volume is,which results in the much multiple shear and improve the plasticity when the specimens are compressed.