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采用粉末冶金方法制备出NiCr/ZrO2功能梯度材料FGMs。通过2种断裂试件研究了材料梯度对混合型断裂行为的影响(FGM A试件,裂纹位于试件的弹性模量较大一侧;FGM B试件,裂纹位于试件的弹性模量较小一侧)。对2种断裂试件在非对称载荷下进行准静态断裂实验,并利用数字散斑相关方法测得Ⅰ、Ⅱ型应力强度因子。结果表明:FGM A的裂纹的开裂角小于FGM B的开裂角;FGM A的弹性梯度对静态裂纹有保护作用;弹性模量的梯度变化和裂尖局部材料的断裂韧性会影响混合型裂纹的启裂。
NiCr / ZrO2 functional graded FGMs were prepared by powder metallurgy. The effect of material gradient on the fracture behavior of the composite was investigated by two kinds of fracture specimens (FGM A specimen with crack located on the larger elastic modulus side of the specimen; the modulus of elasticity of specimen FGM B, Small side). Quasi-static fracture tests on two kinds of specimens under asymmetric load were carried out. The type I and type II stress intensity factors were measured by digital speckle correlation method. The results show that the crack initiation angle of FGM A is smaller than the cracking angle of FGM B. The elastic gradient of FGM A has a protective effect on the static crack. The gradient of elastic modulus and the fracture toughness of the local material at crack tip will affect the crack initiation crack.