通过室温压缩试验,研究全片层γ-TiAl基合金在不同加载速度和不同卸载载荷下的压缩断裂行为.结果表明:随着加载速度的增加,γ-TiAl基合金试样的屈服强度及抗压强度相应增大;试样的最终断裂是通过裂纹的形核、扩展以及相互贯通而形成的,断裂面主要由剪应力形成的撕裂区和压应力形成的解理断裂区域组成,并且在不同加载速度下,断口也呈现出规律性的变化.在不同载荷加载-卸载-再加载的过程中,小载荷(4.67、9.42、18.94 kN)下卸载和加载的名义应力-名义应变曲线完全重合,大载荷(26.60、37.24、53.20 kN)下卸载后产生的不可逆应变依次增大;裂纹面密度随着卸载载荷的增大而逐渐增大,材料的损伤程度不断增加.%Compressive fracture behavior of fully lamellar γ-TiAl-based alloy under different loading speeds and unloadings was studied in the compression tests at room temperature. The results show that,with the increase of loading speed,the yield strength and compressive strength of the samples increase. The samples fracture eventually through the path of crack nucleation,propagation and coalescence. The fracture surface are mainly composed of tearing region due to the shear stress, and cleavage fracture region due to the compressive stress. And the fracture morphologies also change regularly with different loading speeds. In the loading-unloading-reloading process,the nominal stress vs strain curves coincide when the unloads are small (4. 67 ,9. 42 ,18. 94 kN ),but the reversible strain increases when the uploads are large (26. 60,37. 24,53. 20 kN). The surface density of cracks increases and the damage of material is also increases with increasing unloads.
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