【摘要】 采用反挤压试验结合数值模拟的方法,研究了块体非晶合金在过冷液态区内成形微小零件的变形行为。首先采用材料压缩试验确定非晶合金的成形温度和成形速率,并用Deform3D软件模拟压缩试验过程,以寻找一个和非晶合金成形过程类似的材料,获得一个相似的本构关系,用于后续反挤压过程的模拟。在此基础上,进行了外径为1.2mm,内径1.0mm圆筒形零件的反挤压试验,研究了温度和冲头速率对反挤压力的影响,结果表明成形温度对反挤压力的影响较大,而成形速率对反挤压力的影响不显著。采用SEM观察成形件的表面形貌,发现零件的尺寸精度较高,表面精度较差。计算表明挤压过程中的摩擦较大,Deform3D模拟表明应变速率分布极不均匀。更多还原

【Abstract】 The microforming behavior of Zr-based bulk metallic glass in the supercooled liquid region was investigated by back extrusion combined with numerical simulation. Firstly, the stress-strain relation was established by uniaxial compression tests. The temperature and forming speed were determined as well. A simulation on compression tests by Deform3D was performed to find out similar materials and constitutive equation that were used later. Based on the result, parts with an outer diameter of 1.2 mm and inner diameter of 1.0 mm were formed by back extrusion. SEM indicates that the parts were formed with high dimensional precision but poor surface finish. The simulation by Deform3D shows that the friction in back extrusion is greater than that expected and the distribution of strain rate is highly non-uniform.更多还原