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在含孔隙微纳晶材料受单轴压缩载荷下的大塑性变形中,由于孔洞与基体变形的不匹配,在孔洞周围将产生大量的几何必需位错,论文假设这些位错均匀地从孔洞表面向其内部发射,促使孔洞周围先产生局部非均匀变形,从而导致微纳晶镍试样内孔隙率的变化.基于这种假设论文首先建立了单轴压缩载荷下孔洞的演化发展模型,并用此模型预测了孔隙率的变化,将其与实验测定值进行了比较,结果表明孔洞演化发展模型具有一定合理性.在此基础上,讨论了固定孔隙率和演化发展的孔隙率对不同晶粒尺寸和不同应变速率下的微纳晶镍试样力学行为的影响.
In the plastic deformation of pore-containing micro-nanocrystalline materials under uniaxial compressive loading, a large number of geometrically necessary dislocations will be generated around the pores due to the mismatch between the pores and the deformation of the matrix. It is assumed that these dislocations are uniformly distributed from the surface of the pores To the internal emission, to promote the local non-uniform local deformation around the hole, resulting in changes in the porosity of the micro-nano-nickel sample.Based on this assumption, the paper first established a uniaxial compression load evolution of the hole model and use this The model predicts the change of porosity and compares it with the experimentally measured values, and the results show that the model of pore evolution and development has some rationality.On the basis of this, it is discussed that the fixed porosity and the evolution of porosity have different effects on the grain size And the mechanical behavior of micro-nano-nickel samples at different strain rates.