Investigation into cadmium embrittlement of landing gear wheel axles

摘要

There are two landing gear wheel axles, called, respectively, 1# and 2#. Axle 1# was not carried through cadmium stripping prior to stress annealing, and the repair process of axle 2# had cadmium stripping before stress relieving. In order to confirm if there is cadmium embrittlement in the landing gear wheel axles, a series of experimental analyses were carried through and some conclusions were obtained. There is no cadmium diffusion in 1# and 2# axles and risk of cadmium embrittlement can be excluded. High compressive stress exists on surface of 1# and 2# axles and shot peening is effective. Cadmium layer was oxidized approximately 0.35 mu m from outer surface, but the oxidized layer has not attacked the base material. The prerequisites of cadmium embrittlement were studied. The three prerequisites of cadmium embrittlement are cadmium, a certain tensile stress and a certain temperature. Disappearance of any one of the prerequisites can avoid cadmium embrittlement as verified by our experiments.