Some SEM observations on high-temperature fracture in aluminum

Abstract

A scanning electron microscope has been employed to study fracture in A1 under creep and low cycle fatigue conditions at high temperatures. For purposes of comparison, fracture of A1 at room temperature in tension and low cycle fatigue has been examined. The conclusion emerges that fracture mode of A1 during creep at 548 K (0.59 T_m, where T_m is the melting temperature in degrees Kelvin) is analogous to tensile fracture at the ambient temperature. On the other hand, under low cycle fatigue loading, fracture at the higher temperature, namely 648 K (0.69 T_m), is significantly different with fatigue, ductile, and intergranular rupture components constituting a mixed fracture mode in comparison to the almost-complete fatigue fracture at room temperature. Some details concerning the creep and high-temperature fatigue fracture processes have also been noted.