仿生非光滑表面45#钢模具的热疲劳性能

利用动物体表仿生学原理制备45#钢模具非光滑表面试样,通过自约束冷热疲劳试验方法,对比研究了光滑与非光滑试样的热疲劳特性,观察分析了热疲劳裂纹在仿生非光滑表面上扩展的形貌和内部机理.结果表明,非光滑单元体对热疲劳裂纹有阻断作用,仿生非光滑表面使模具的热疲劳抗力显著提高,模具表面的热疲劳性能在非光滑单元体的某一密度范围内达到最佳状态.在细晶强化、合金强化等强化机制下,由仿生非光滑单元体构筑的"桩钉"效应是导致模具抗热疲劳性提高的主要原因.

Thermal fatigue behavior of 45 steel die with bionic unsmoothed surface

According to the investigation of bionics, the unsmoothed topography of some biology generally shows a perfect configuration and a reasonable dynamic performance. This is the result of their evolution and optimization to adapt themselves to the environment for millions of years. Based on this theory above, the bionic unsmoothed surface specimen of 45 steel die was manufactured by alloy smearing and laser-texture technique. With the self-restricting test method, the number and length of thermal fatigue crack on different specimens was compared, the crack morphology was investigated, and the microstructure in bionic unsmoothed unit was analyzed. It can be found out that the thermal fatigue resistance was improved evidently on bionic unsmoothed surface, and the thermal fatigue behavior of 45 steel die can reach the best within a density range of bionic unsmoothed unit. The "stake-nail" effect produced by bionic unsmoothed unit under conditions of some strengthening mechanism are main reason to reinforce the thermal fatigue resistance.