Effect laws and mechanisms of different temperatures on isothermal tensile fracture morphologies of high-strength boron steel

The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also analyzed based on the relationship between microstructure transformation and continuous cooling transformation(CCT) curves. It is found that 1) fractures of the investigated steel at high temperatures are dimple fractures; 2) the deformation of high-strength boron steel at high temperatures accelerates diffusion transformations; thus, to obtain full martensite, a higher cooling rate is needed; and 3) the investigated steel has the best plasticity when the deformation temperature is 750 °C.     

航空润滑油氧化衰变影响因素及检测方法综述

航空润滑油在高速、高温且有金属催化的工作条件下极易被氧化,氧化导致的油品理化性能变化将直接影响润滑系统的正常工作,甚至危及飞机的安全飞行,因此加强对滑油的氧化衰变情况检测非常重要。论文简要分析了滑油氧化衰变的机理、危害及影响因素,对常用的检测方法进行了综述,并分析比较了检测方法的优缺点。