平板撞击下梯度镍的层裂损伤研究

Spallation damage of gradient nickel under planar impact

为研究高应变率下梯度镍的层裂损伤行为,对均匀镍材进行准静态扭转,制备出硬度和晶粒尺寸沿径向规则变化的圆柱形梯度镍。运用一级轻气炮对梯度镍进行平板撞击加载,利用多通道激光多普勒测速仪测量梯度镍的自由面粒子速度,计算层裂强度,并结合金相显微镜观察梯度镍回收试样的层裂损伤形貌。实验结果表明:平板撞击加载下,梯度镍的层裂损伤以沿晶断裂为主,并伴随少量晶内形核的孔洞;沿梯度方向,随着硬度的增加,层裂强度和损伤度分别增加和减小;随着撞击速度的提升,梯度镍的层裂强度逐渐升高,损伤度也相应地增加。

The spallation damage of gradient nickel at high strain rate is investigated via planar impact experiments.The uniform nickel plate is subjected to quasi-static torsion to prepare the cylindrical gradient nickel with varying hardness and grain size along the radial direction.A single-stage gas gun is utilized to impact the gradient nickel.The free surface particle velocities of gradient nickel which can be used to calculate the spallation strength,are measured with multi-channel laser Doppler velocimeter.The spallation damage morphology of the recovered samples is characterized by metallographic microscope.The experimental results show that the spallation damage of gradient nickel under planar impact is mainly intergranular fracture,accompanied by a few intragranular voids.Along the gradient direction,the spall strength increases and the damage degree decreases with the increase of hardness.As the impact velocity rises,the spall strength of gradient nickel and corresponding damage degree increase.