Investigation into cadmium embrittlement of landing gear wheel axles

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 μm 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.