Busk, R. S.
Metallurgist, The Dow Chemical Co., Midland, Mich.
Pages: 12 Published: Jan 1943
A Method for the quantitative rating of radiographs showing porosity in magnesium base alloys is described. By varying the intensity of the viewing light with a Variac, and noting the voltage at which porosity is just visible, a scale is established for the rating of radiographs. This scale is then used to study the effect of microporosity on the tensile properties of Dowmetal H alloy in the as-cast and solution heat treated states; the tensile properties of C alloy in the as-cast, solution treated and heat treated and aged states; and the fatigue strength of C alloy in the solution heat treated state.
It is noted that C alloy will be less porous than H alloy under similar foundry conditions. But with a given amount of porosity H alloy will suffer a smaller loss of strength than C alloy. The tensile strength of both alloys falls as the amount of porosity increases, but the yield strength is unaffected until very large amounts of porosity are present. The fatigue strength of solution heat treated C alloy is affected to the same degree as is the tensile strength for a given amount of porosity.
Paper ID: STP43911S