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The purpose of this study was to conduct a comparative corrosion assessment of alloys and coating schemes of interest for the fabrication of multi-material lightweight vehicle architectures. Alloys considered for this application included galvanized high strength low alloy steel, aluminum alloy AA6111 and magnesium alloy ZEK100. The coating scheme considered for corrosion protection included a layered paint top-coat scheme that was applied to a pre-treated surface. The pre-treatments included an alloy-specific commercial conversion coating (CC) and a plasma electrolytic deposition (PED) process that was applied only to the ZEK100 material. The corrosion assessment of the scribed coated alloy panels was conducted after 1000 h exposure in the ASTM B117 salt fog environment. Characterization of the mode and extent of corrosion damage observed and the role played by the exposed alloy microstructure utilized both light optical microscopy and electron microscopy.

The purpose of this work was to initiate a comparative evaluation of the aqueous corrosion resistance of ferritic stainless steels currently used to fabricate automotive exhaust systems. Both acid condensate and double loop electrochemical potentiokinetic reactivation (DL-EPR) testing using both as-received and heat treated test coupons prepared from Types 409, 409Al, 436 and 439 stainless steel was conducted for this purpose. A truncated version of an in-house acid condensate testing protocol revealed that Type 409Al stainless steel was the most resistant to corrosion of the four ferritic stainless steels examined, whereas Type 409 stainless steel was the least resistance to corrosion.

Using standard tensile testing methods, the material properties of AKDQ and DP600 steels tubes along the axial direction were determined. A novel in-situ optical strain mapping system ARAMIS® was utilized to evaluate the strain distribution during tensile testing along the axial direction. Microstructural and damage characterization was carried out using microscopy and image analysis techniques to compare the damage evolution and formability of both materials. Failure in both steels was observed to occur via a ductile failure mode. AKDQ was found to be the more formable material as it can achieve higher strains, total elongations and thinning prior to failure than the higher strength DP600.

The application of high strength steels in tube hydroforming is being considered as one of the most effective ways to achieve the overall weight reduction without compromising the vehicle safety (crashworthiness). In this paper, the tensile behaviour of high strength dual-phase steel DP600 was investigated. The microstructure, mechanical performance and damage evolution was evaluated. A new finite element (FE) model based on crystal plasticity theory was developed to investigate large strain phenomena in multi-phase materials.