Zr35Ti30Cu8.25Be26.75非晶合金在高速率下的高温流变本构模型

High temperature rheological constitutive model of Zr35Ti30Cu8.25Be26.75 amorphous alloy at high strain rate

为研究锆基非晶合金在过冷液相区内较高温度区间和较高应变速率变形条件下的流变行为,准确描述温度和应变速率对非晶合金流变应力的影响,用Zwick/Roell力学性能实验机对Zr35Ti30Cu8.25Be26.75非晶合金进行高温(~1.2Tg)较高速(~100/s)下的压缩实验,分别采用虚应力模型和提出的Maxwell-Pulse本构模型进行了应力、应变关系的表征。结果表明:Zr35Ti30Cu8.25Be26.75非晶合金的流变行为具有较强的温度和应变速率敏感性,即随着温度的降低和应变速率的升高,非晶合金的流变应力单调增加,同时其变形行为由平衡态牛顿流变转变为非平衡态的非牛顿流变;对比实验数据和模型预测数据发现,虚应力模型拟合结果偏差较大,误差大于50%,而Maxwell-Pulse本构模型预测值与实验值一致性好,准确率在90%以上,说明Maxwell-Pulse本构模型不仅能够同时描述Zr35Ti30Cu8.25Be26.75非晶合金的牛顿流变和非牛顿流变现象,也能够准确地反映Zr35Ti30Cu8.25Be26.75非晶合金在高温和较高应变速率变形条件下的应力应变关系。

In order to study the rheological behaviors of Zr35Ti30Cu8.25Be26.75 amorphous alloys during deformation at high temperatures and highstrain rates within the supercooled liquid region, compression tests at high temperatures(~1.2Tg) and higher speeds(~100/s) were carried out with a Zwick/Roell machine. The results show that the rheological behaviors of Zr35Ti30Cu8.25Be26.75 amorphous alloy is sensitive to temperature and strain rate. With the decrease of temperature and the increase of strain rate,the flow stress of amorphous alloy increases monotonously,and its deformation behavior changes from equilibrium Newtonian flow to non-equilibrium non-Newtonian flow. In order to accurately describe the effects of temperature and strain rate on the flow stress, the Fictive stress model and the Maxwell-Pulse constitutive model were used. The experimental data and model prediction data show that the fitting results of the Fictive stress model have large deviations with an error of greater than 50%, but the predicted values of the Maxwell-Pulse constitutive model are in good agreement with the experimental values(the accuracy is higher than 90%).The result indicates indicating that the Maxwell-Pulse constitutive model can not only describe the Newtonian and non-Newtonian flow phenomena, but also accurately reflect the stress-strain relationship of Zr35Ti30Cu8.25Be26.75 amorphous alloy under high temperature and high speed deformation conditions.