Compression fatigue properties of open-cell aluminum foams fabricated by space-holder method

摘要

The compression-compression fatigue properties of open-cell Al foams fabricated by space-holder method with different porosities were investigated. The epsilon-N curves of the Al foams show two types based on the stress levels (k). The first type shows a three-stages for low stress level (k 0.9), while the second type only presents stage I and stage III for high stress level (k = 0.9). The quasi-static compression tests were performed to determine the yield strength (sigma(s)) of Al foams. The fatigue strengths of Al foams with porosities of 50%, 60% and 70% are 12.77 MPa (0.75 sigma(s)), 7.61 MPa (0.68 sigma(s)) and 3.02 MPa (0.66 sigma(s)) respectively, showing a linear decrease with the increment of porosity. The macroscopic deformation observation shows that the local deformation regions during fatigue tests emerge earlier than those during quasi-static compression tests. The initiation and propagation of fatigue cracks are the main failure mechanism of Al foams subjected to compression fatigue loading.