Christopher Schunk

TL;DR: In this article, a bimodal grain size distribution and alternating layers of commercial purity aluminum and high purity aluminum (Al99.999) were successfully processed by accumulative roll bonding at room temperature up to 8 cycles.

TL;DR: In this article, the influence of gradients in hardness and elastic properties at interfaces of dissimilar materials in laminated metallic composites (LMCs) on fatigue crack propagation is investigated experimentally for three different LMC systems: Al/Al-LMC, Al/Ti/Steel LMCs, and Al/LMC with dissimilar yield stress and Young modulus.

Abstract: Accumulative roll bonding (ARB) is a very useful method to produce ultrafine‐grained (UFG) sheet material with extraordinary mechanical properties. Besides the production of UFG mono‐materials, it is possible to create tailored multicomponent materials by stacking different materials. In this work, the aluminum alloy AA2024 and titanium grade1 are roll‐bonded in order to achieve laminated metal composites (LMC) with an UFG microstructure. The mechanical properties and microstructural evolution during the ARB process of the LMC are analyzed and compared to that of LMCs. The mono‐materials show an ultrafine grain structure after at least three ARB cycles which results in an increased yield and ultimate tensile strength. Most interestingly, the produced LMCs exhibit mechanical properties which are way better than the properties of the UFG mono‐materials, when a linear rule of mixture is applied. The strength of the titanium–aluminum laminate is very close to the strength of the UFG titanium. Although, the density is significantly lower. The light‐weight potential of the LMC is best expressed by the specific strength. Compared to the specific strength of UFG mono‐material titanium of about 168 Nm g−1 and UFG mono‐material aluminum of about 195 Nm g−1 the ARB laminate exhibits the highest specific strength of about 217 Nm g−1 after three cycles.