Cybermaterials innovation entails an integration of Materials by Design and accelerated insertion of materials (AIM), which transfers studio ideation into industrial manufacturing. By assembling a hierarchical architecture of integrated computational materials design (ICMD) based on materials genomic fundamental databases, the ICMD mechanistic design models accelerate innovation. We here review progress in the development of linkage models of the process-structure–property-performance paradigm, as well as related design accelerating tools. Extending the materials development capability based on phase-level structural control requires more fundamental investment at the level of the Materials Genome, with focus on improving applicable parametric design models and constructing high-quality databases. Future opportunities in materials genomic research serving both Materials by Design and AIM are addressed.

/pdf/cybermaterials-materials-by-design-and-accelerated-insertion-biywil31y4.pdf

Cybermaterials: materials by design and accelerated insertion of materials

A novel strengthening and toughening strategy for T250 maraging steel: Cluster-orientation governed higher strength-ductility combination induced by electropulsing

Seamless tubing of C-250 maraging steel manufactured by the flow forming technique was joined by the electron beam welding process. Various post-welding heat treatments were conducted to improve the overall mechanical properties of the welded tubing. For the 480°C/6 h/air cooling post-weld aging treated maraging steel, a significant increment of 11% reversion austenite was present in the weld metal. Only the tensile strength of this aging treated metal met the required specification while its percentage elongation reached only 50% of the specification, attaining only 35% of the strength of the parent metal. For the post-welded solution + aging treated maraging steel, only the yield strength met the specification. Moreover, a significant amount of reversion austenite pools was also present at the grain boundaries of the material located at the weld metal. Although the homogenisation treatment could improve the hardness of the weld metal, it failed to have the tensile strength of the steel met the s...

Effect of post-weld heat treatments on microstructure and mechanical properties of electron beam welded flow formed maraging steel weldment

In developing compositions for new ultra-high strength steels it is important to understand the effects of alloying additions on the microstructure, strength and fracture resistance. Cobalt has been widely used in the development of high toughness ultra-high strength steels and the effects of cobalt on the strength of steels has been studied extensively but there is remarkably little known about how cobalt influences toughness. In this article are reviewed the effects of cobalt on the toughness of steel. The literature suggests that cobalt in solid solution will act to raise the ductile-to-brittle transition temperature but that it can act to increase the upper-shelf toughness of steel.

Cobalt and the Toughness of Steel

The technique of forward flow forming has been used to produce a long and thin wall tube of C-250 maraging steel The work hardening effect of solution treated C-250 by flow forming is small Therefore aging treatment after flow forming is required to increase hardness and strength Final formed C-250 tubes are usually manufactured by combining aging treatment and electron beam welding (EBW) The hardness and tensile strength of aged C-250 maraging steel weldment decreased to the corresponding values obtained in the solution annealed state Thus, the formed tube by EBW requires stress relieving treatment (and similarly for theaged condition) to increase hardness and strength and thus meet the required specification The strength requirement was successfully achieved but the elongation of the aged, EBW, and stress relieved specimen was 885% lower than that of the unwelded specimen

Effect of stress relief on microstructure and mechanical properties of flow formed maraging steel weldment by electron beam welding

The addition of Co to 18%Ni maraging steels produces an increase in hardness due to a synergistic effect. A similar effect is reported in this paper for maraging steels based on Fe–5Mn–6Ni. However, Co is thought to have an effect on the ductile-brittle transition temperature (DBTT) of mar aging steels. The addition of 9%Co to the base alloy plus 2·5%Mo increases the DBTT to 120°C in unaged material. Similar to reports by other workers on Fe–Co alloys, it is considered that this increase in DBTT is due to Co restricting cross-slip. In contrast, Mo is thought to lower the DBTT by increasing cross-slip. The reason for 2·5%Mo changing the mode of brittle fracture from intergranular to transgranular cleavage in the base alloy is discussed. Mention is also made of the effect of Ni on the DBTT in lath martensite structures. In classical 18%Ni maraging steel, the DBTT of the Fe–18Ni base is probably so low that the addition of Co does not seriously embrittle the steel.MST/1828

D. R. Squires

Papers

Effect of cobalt on impact toughness of steels