Microstructure evolution of medium‑manganese Al-alloyed steel manufactured by double-step intercritical annealing: Effects of heating and cooling rates

A novel double-step intercritical annealing (DSIA) process was conducted on Fe-0.16C-4.7Mn-1.6Al-0.2Si transformation induced plasticity (TRIP) steel. In a present study, an effect of different heating and cooling rates applied to the second intercritical annealing (IA) step on the microstructure was studied in detail by using scanning...

Microstructure and Dynamic Mechanical Behavior of Thermomechanically Rolled 3Mn–Al and 5Mn–Al Sheet Steels

The comparison of the dynamic mechanical behavior and microstructure of two medium manganese sheet steels (3Mn–Al and 5Mn–Al) alloyed with aluminum is aimed. Mechanical properties under dynamic tensile loads are determined by means of rotary hammer dynamic tests at strain rates of 250 and 1000 s⁻¹ and analyzed together with the...

The effect of nano-sized κ-carbides on the mechanical properties of an Fe-Mn-Al-C alloy

The strengthening via precipitation of nano-sized κ-carbides leads to exceptional strength-ductility balance in low-density steels. During aging, such nanocarbides form through spinodal decomposition by fluctuations in the aluminum and carbon content in the austenite, followed by short-range ordering. At lower aging temperatures and short...

Improving the strength-ductility balance of medium-Mn Q&P steel by controlling cold-worked ferrite microstructure

The phase transformations, microstructure and properties of two Medium-Mn processed via quenching and partitioning steels were compared in this contribution and a new strategy for controlling mechanical properties by introducing and controlling cold-worked ferrite prior to heat treatment is proposed. It was found that during heating, the...

Strain partitioning and damage initiation in a continuously cooled carbide free bainitic steel

Microscopic stress and strain partitioning control the mechanical and damage behavior of multiphase steels. Using a combined numerical and experimental approach, local strain distributions and deformation localization are characterized in a carbide free bainitic steel produced by continuous cooling. The microstructure of the steel consists of...

Influence of chemical segregation on bainitic microstructures in a carburized bearing steel

Bainite to austenite reversal is one of the grain refinement techniques employed in carburized steels. However, chemical segregation influences the homogeneity of the bainitic structure, which is seminal to exploit the advantages associated with austenite reversal. It is therefore important to understand the influence of chemical segregation...

Bainite plate thickness reduction and microstructure tailoring by double austempering of Al-rich 3Mn steel

The novel use of double austempering treatments in a multiphase steel to refine and homogenize the final microstructure and thus improve the material strength have been studied in the 3.3Mn-0.17C-1.6Al-0.23Mo-0.22Si alloy. The microstructural features developed after conventional isothermal austempering treatments at 450 °C and 400 °C were...

Microstructure, mechanical, and corrosion properties of Zr_1-xCr_xB_y diboride alloy thin films grown by hybrid high power impulse/DC magnetron co-sputtering

We study microstructure, mechanical, and corrosion properties of Zr_1-xCr_xB_y coatings deposited by hybrid high-power impulse/DC magnetron co-sputtering (CrB₂-HiPIMS/ZrB₂-DCMS). Cr/(Zr + Cr) ratio, x, increases from 0.13 to 0.9, while B/(Zr + Cr) ratio, y, decreases from 2.92 to 1.81. As...

Microstructural investigation and identification of intermetallic σ-phase in solution annealed 316L-type austenitic stainless steel

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is an accelerator driven system, currently under development at SCK CEN in Mol, Belgium. This nuclear system will use liquid Lead-Bismuth eutectic alloy as a spallation target for fast neutron production and as coolant. The ideal structural material for a liquid metal...

Influence of microstructure on mechanical properties of bainitic steels in railway applications

Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural...

The effect of heating rate and soaking time on microstructure of an advanced high strength steel

This work focuses on the effect of soaking time on the microstructure during ultrafast heat treatment of a 50% cold rolled low carbon steel with initial ferritic-pearlitic microstructure. Dilatometry analysis was used to estimate the effect of heating rate on the phase transformation temperatures and to select an appropriate inter-critical...

Study of carbide dissolution and austenite formation during ultra–fast heating in medium carbon chromium molybdenum steel

In this study, UltraFast Heat Treatment (UFHT) was applied to a soft annealed medium carbon chromium molybdenum steel. The specimens were rapidly heated and subsequently quenched in a dilatometer. The resulting microstructure consists of chromium-enriched cementite and chromium carbides (in sizes between 5–500 nm) within fine (nano-sized)...

Defect evolution during annealing of deformed FeSi alloys studied by positron annihilation spectroscopy

High silicon steel is widely used in electrical appliances. Alloying iron with silicon improves its magnetic performance. A silicon content up to 6.5 wt. % gives excellent magnetic properties such as high saturation magnetization, near zero magnetostriction and low iron loss in high frequencies. Their workability is greatly reduced by the...