FeAl金属间化合物多孔材料压缩力学性能

Compression Mechanical Properties of FeAl Intermetallic Compound Porous Material

针对本课题组采用元素混合粉偏扩散-反应合成-粉末烧结方法制备的Fe-40at%Al金属间化合物多孔材料,采用单轴压缩实验研究其压缩应力-应变曲线特征以及孔隙率对其力学性能的影响规律,并通过扫描电镜实验揭示其微观断裂机理。结果表明:FeAl多孔材料的压缩应力-应变曲线可分为弹性、屈服、强化和破坏4个阶段,其中较大孔隙率的FeAl多孔材料表现出明显的非线性弹性特征;随着孔隙率的增大,其压缩屈服极限变化不大,而弹性模量和抗压强度显著降低;其断口特征宏观上表现为脆性断裂,微观上为微观沿晶断裂。比较FeAl多孔材料的理论值E*和实测值E可知,非均匀Plateau多孔结构细观力学模型不适合高密度多孔材料,但可以较好地预测中密度多孔材料的弹性模量。

Fe-40at%A1 intermetallic compound porous material prepared by an element mixture partial diffusion-reactive synthesis-sintering method was researched by a uniaxial compression test in order to analyze its characteristics of stress-strain curve and mechanical properties affected by porosity and reveal its microscopic fracture mechanism in compression by scanning electron microscope test. Results show that the compressive stress-strain curves of the FeA1 porous material can be divided into four stages： elasticity, yielding, strengthening and failure, where the larger the porosity （i.e., the lower the relative density）, the more obvious the nonlinear elasticity. With the increase of the porosity, the compressive yield strength changes little, while the elastic modulus and compressive strength significantly decrease. The characteristic of the fracture surface is of brittle fracture in macroscopy and of intergranular fracture in microscopy. Comparing the theoretical values and experimental values of the elastic modulus of FeA1 porous material, it is found that the micromechanical model of heterogeneous Plateau porous structure is more accurate for predicting the effective elastic modulus of the medium-density porous materials but not for the high-density ones.