应力梯度特征对金属镍变形行为与力学性能的影响

Effects of Stress Gradient Characteristics on Deformation Behavior and Mechanical Properties of Pure Nickel

本文针对金属材料镍,利用扭转变形制备了应力/应变梯度分布的特殊结构.结合ABAQUS软件,构建了包含应力梯度特征的有限元模型,系统分析了应力梯度特征在塑性变形过程中的演化规律及其对变形行为与力学性能的影响.结果表明,随着应力梯度的提高,材料的屈服强度从100 MPa提高到240 MPa;应力梯度分布从单一递减分布演化为"V"字型分布特征,屈服行为由连续屈服转化为屈服降;上下屈服点之差从10 MPa增加到60 MPa.

The gradient structure with stress/strain gradient distribution was prepared through torsional deformation in pure nickel metal. The finite element model containing stress gradient distribution characters was established based on ABAQUS software. The stress gradient distribution evolution and its influence on the deformation behaviors and mechanical property were studied by combining the experiment with simulation results. The results indicate that with the increase of stress gradient, the yield strength increased from 100 MPa to 240 MPa, the stress gradient distribution changed from simple decreasing to V-shaped and the yield behavior changed from continuous yield to yield drop. The difference between the upper and lower yield points increased from 10 MPa to 60 MPa.