Metallurgy, the Father of Materials Science

The evolution of the discipline of materials science during the second half of the twentieth century is outlined. The concept emerged in the USA, almost simultaneously in an academic metallurgy department and in an avant garde industrial research laboratory, and its development subsequently all over the world has been a joint enterprise involving universities, industrial laboratories and government establishments. The initial impetus came unambiguously from the well established discipline of physical metallurgy, but from the 1960s onwards, the input from solid state physicists grew very rapidly, while materials chemistry is a later addition. Of all the many subdivisions of modern materials science, polymer science has been the slowest to fit under the umbrella of the broad discipline; its concepts are very different from those familiar to metallurgists. Two fields have contributed mightily to the creation of modern materials science: One is nuclear energy and, more specifically, the study of radiation damage, the other is the huge field of electronic and opto electronic materials in which physics, chemistry and metallurgy are seamlessly combined.

Discovery of marageing steels: machine learning vs. physical metallurgical modelling

Physical metallurgical(PM)and data-driven approaches can be independently applied to alloy design.Steel technology is a field of physical metallurgy around which some of the most comprehensive understanding has been developed,with vast models on the relationship between composition,processing,microstructure and properties.They have been applied to the design of new steel alloys in the pursuit of grades of improved properties.With the advent of rapid computing and low-cost data storage,a wealth of data has become available to a suite of modelling techniques referred to as machine learning(ML).ML is being emergingly applied in materials discovery while it requires data mining with its adoption being limited by insufficient high-quality datasets,often leading to unrealistic materials design predictions outside the boundaries of the intended properties.It is therefore required to appraise the strength and weaknesses of PM and ML approach,to assess the real design power of each towards designing novel steel grades.This work incorporates models and datasets from well-established literature on marageing steels.Combining genetic algorithm(GA)with PM models to optimise the parameters adopted for each dataset to maximise the prediction accuracy of PM models,and the results were compared with ML models.The results indicate that PM approaches provide a clearer picture of the overall composition-microstructureproperties relationship but are highly sensitive to the alloy system and hence lack on exploration ability of new domains.ML conversely provides little explicit physical insight whilst yielding a stronger prediction accuracy for large-scale data.Hybrid PM/ML approaches provide solutions maximising accuracy,while leading to a clearer physical picture and the desired properties.

Some Aspects of High Manganese Twinning-Induced Plasticity (TWIP) Steel, A Review

High manganese twinning-induced plasticity （TWIP） steel is a new kind of structural material and possesses both high strength and superior plasticity and can meet the weight-lightening requirement for manufacturing vehicle body. The excellent formability of the TWIP steel comes from the extraordinary strain hardening effect during plastic deformation. The reduction of specific weight by aluminum alloying and strain hardening effect can lead to an effective weight reduction of the steel components, and provide a better choice for materials in vehicle body design. The TWIP effect in high Mn steels is generally associated with the successive work- hardening generated by twins and influenced by some factors, such as Mn content, AI addition revealed by stacking fault energy （SFE）, grain size, deformation temperature and strain rate. The present review introduces some aspects of the TWIP steels relating to their physical metallurgy, influencing factors associated with their deformation mechanisms, and a prospect for the future investigation is also described. Moreover, as a potential candidate for replacing Ni-Cr austenitic stainless steel, researches on the oxidation behavior and corrosion resistance of Fe-Mn-AI-C system steels are also reviewed.