Pushing and pulling for high strength: High-strength aluminum alloys are important for producing lightweight cars, trains, and airplanes. The traditional strategy for doing this is through hours of high-temperature cycling to form precipitates in the alloy. Sun et al. developed a processing method that relies on mechanical cycling by pushing and pulling on the alloys at room temperature. This quickly creates many very fine precipitates that have the same strengthening effect as those characteristic of traditional thermal methods. This method should also work for other alloy systems. Science , this issue p. 972
7 September 2022 in Materials Science and Engineering: A
A novel variable temperature rolling (VTR) and annealing process was conducted on a metastable austenitic stainless steel. Strain softening occurred during tensile straining in both cold rolled and cryogenic rolled-annealed steels, leading to low uniform elongations of only 2-3%. In contrast, thanks to the metastable dual-phase heterogeneous lamellar structure achieved via the VTR process, a ultra-high strength of over 1 GPa was obtained, and strain hardening led to a remarkable increase of uniform elongation up to 10%. The high strength and ductility are attributed to the significant work-hardening derived from the superior heterogeneous deformation-induced hardening and sustained transformation-induced plasticity effect. GRAPHICAL ABSTRACT IMPACT STATEMENT We identify a new variable temperature rolling and annealing process to achieve a metastable dual-phase heterogeneous lamellar structure, which overcomes strength-ductility trade-off by coupling of HDI hardening and TRIP effect.