Lean Wrought Magnesium Alloys

Lean magnesium alloys are considered attractive candidates for easy and economical hot forming. Such wrought alloys, defined here as materials with a maximum alloying content of one atomic or two weight percent, are known to achieve attractive mechanical properties despite their low alloy content. The good mechanical properties and the considerable hardening potential, combined with the ease of processing, make them attractive for manufacturers and users alike. This results in potential uses in a wide range of applications, from rolled or extruded components to temporary biomedical implants. The characteristic behavior of these alloys and the optimal use of suitable alloying elements are discussed and illustrated exemplarily.

Analytic Binary Alloy Volume–Concentration Relations and the Deviation from Zen’s Law

Alloys expand or contract as concentrations change, and the resulting relationship between atomic volume and alloy content is an important property of the solid. While a well-known approximation posits that the atomic volume varies linearly with concentration (Zen’s law), the actual variation is more complicated. Here we use the apparent size of the solute (solvent) atom and the elasticity to derive explicit analytical expressions for the atomic volume of binary solid alloys. Two approximations, continuum and terminal, are proposed. Deviations from Zen’s law are studied for 22 binary alloy systems.

Chemical Component Optimization Based on Thermodynamic Calculation of Fe-1.93Mn-0.07Ni-1.96Cr-0.35Mo Ultra-High Strength Steel

Due to the complex composition and high proportion of alloys in traditional ultra-high-strength steel, the dilemma caused by ultra-high strength and low toughness in casting and forging forming processes requiring subsequent heat treatment can be mitigated with an efficient and economical rolling process. In this work, a thermodynamic model is proposed to calculate the change in the mechanical response due to the thermal contribution based on alloy phase diagrams. The influence of alloy content on precision laws was analyzed, and the chemical component was optimized. A verification simulation without real experiment was conducted to study the potential and limitations of the alloy content on mechanical properties. The results showed that the main equilibrium phases and the phases’ chemical compounds were clarified. The influences of Ni, Mo, Cr, and W on transformation laws were elucidated in detail, and the main optimized composition was determined to be 0.23C, 1.96Si, 1.93Mn, 0.07Ni, 1.96Cr, and 0.35Mo. At a cooling rate of 10 °C/s, the content of optimized alloying element fully performed its role in steel, verifying that the chemical component system was in the optimal range. The thermodynamic models and our conclusions have the potential to be generalized for many other materials and process configurations without requiring extensive material testing.