晶粒尺寸对纳晶材料断裂韧性的影响

Effects of grain size on fracture toughness of nanocrystalline materials

建立了一个描述在纳晶材料中特殊旋转变形对裂纹钝化的影响的晶粒相关理论模型。特殊旋转变形由裂纹尖端的应力集中来驱动。由于特殊旋转变形导致临界裂纹强度因子增加,从而达到裂纹的钝化作用。计算了裂纹强度因子与晶粒尺寸的关系,结果显示由于晶粒的特殊旋转变形,使临界裂纹强度因子最大增加到50%。

A grain size dependent theoretical model was established to describe the effect of special rotational deformation on crack blunting in deformed nanocrystalline materials.The special rotational deformation was driven by the stress concentration near the crack tip.The special rotational deformation led to an increase of critical crack intensity factor and it served as a toughening mechanism.The dependence of critical crack intensity factors on grain size was calculated.The result was demonstrated that the special rotational deformation led to a maximum increase of critical crack intensity factor by 50%.