Category: Environmental

Environmental

Establishing a quantifiable tarnish timeline for comparison of anti-tarnish processes in metals

Brass samples were controllably tarnished using the thioacetamide accelerated corrosion (ISO 4538:1995) and synthetic sweat (ISO 3160–2:2003) methods. Spectrophotometry, energy dispersive X-ray spectroscopy (EDX) and electrochemical impedance spectroscopy (EIS) were performed on samples tarnished for set exposure times over seven days. Synthetic sweat produced a loose surface corrosion layer, which limited the use of EIS and spectrophotometry, but for the thioacetamide method both measurements produced … Continue reading Establishing a quantifiable tarnish timeline for comparison of anti-tarnish processes in metals

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Environmental, Nickel, Superalloys

Localized microstructural characterization of a dissimilar metal electron beam weld joint from an aerospace component

Hydrogen induced cold cracking (HICC) and hydrogen embrittlement (HE) are influenced by the microstructural evolution, residual plastic strain (i.e. local misorientation), recrystallization of grains and the resultant grain boundary characteristic distribution (GBCD) brought about by welding processes. HICC and HE are known to cause failures in aerospace components and it is vitally important to quantify the microstructural evolution, degree of residual plastic strain and determine … Continue reading Localized microstructural characterization of a dissimilar metal electron beam weld joint from an aerospace component

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Environmental, Fatigue, Nickel, Peening, Superalloys

Factors affecting the corrosion fatigue life in nickel based superalloys for disc applications

The nickel based superalloy 720Li is employed in the gas turbine due to its mechanical performance at elevated temperature. A comprehensive assessment of the materials behaviour under representative service conditions is reported to address the drive for ever increasing temperatures and more arduous environmental exposure. Fatigue experiments have been performed in an air and air/SOx environment at 700 ∘C containing a mixed salt as a contaminant. … Continue reading Factors affecting the corrosion fatigue life in nickel based superalloys for disc applications

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