In this study, we use molecular dynamics (MD) simulation to explore how Fe–Cr–Ni alloys change their structure when stretched or compressed from two directions at a steady rate and at room temperature. Bi-axial tensile deformation causes changes in stress, creates stacking faults and dislocations, and leads to a change from FCC-to-BCC phase, forming networks of stacking faults that are rectangular and square-shaped. In contrast, when materials are squeezed from two sides, they quickly become unstable, leading to a fast increase in dislocations, which then disappear and rearrange. The FCC-to-BCC transformation starts sooner during compression, creating a mix of FCC and BCC structures with a lot of twinning and honeycomb-like dislocation patterns close to failure. These results highlight the distinct deformation mechanisms under bi-axial loading, emphasizing phase transformation and dislocation dynamics in mechanical behavior. Understanding atomic-level interactions between deformation and phase change is crucial for designing high-strength Fe–Cr–Ni alloys, addressing a key challenge in materials research.

The increasing demand for fuel-efficient and lightweight vehicles has driven the development of advanced-high-strength steels (AHSS), particularly for electric vehicle (EV) applications. In this study, the microstructure and mechanical properties of a 3.5 wt.% medium-manganese steel (MMS) were investigated following intercritical annealing (IA) at 660, 700, and 740 degrees C for 3 minutes. The steel exhibited a multiphase microstructure comprising ferrite, retained austenite (RA), and thermally induced martensite depending on the IA temperature. EBSD analysis revealed maximum RA fraction (similar to 7%) and recrystallization (similar to 78%) at 700 degrees C, which also corresponded to the most favorable mechanical performance with an ultimate tensile strength (UTS) of 1225 MPa, 13% total elongation, and a UTS x elongation product of 15.93 GPa%. The IA-660 degrees C sample showed superior ductility (18%) but lower UTS, while IA at 740 degrees C led to the formation of thermal martensite, yielding high strength (1325 MPa) but poor ductility (6%). The work hardening behavior and deformation-induced martensitic transformation were strongly influenced by the stability of retained austenite, which was controlled by the IA temperature. These findings highlight the potential of optimizing IA parameters to tailor strength-ductility synergy in medium-Mn steels for applications in automotive industries.

Aluminium plays a vital role in large-scale manufacturing for the aerospace and automotive industries owing to its low density and excellent corrosion resistance. Additionally, it is extensively utilized in packaging industries, including those for food, electronics, and pharmaceuticals. This study employs large-scale molecular dynamics simulations to examine the structural evolution and phase transitions of aluminium during multi-axial straincontrolled cyclic deformation. Uniaxial, biaxial, and triaxial cyclic loading resulted in distinct deformation paths, including dislocation nucleation, grain coarsening, and FCC to BCC/HCP transitions. Quantitative study showed yield strength of 1.807 GPa (Uniaxial) and 4.67 GPa (Triaxial), with up to 50 % FCC to BCC phase transition during the multi-axial cyclic deformation. Mechanistically, BCC formation was trigged by localised stress concentrations and defect interactions, which provided an alternative pathway for accommodating cyclic strain. Sigificantly, these predicted FCC to BCC/HCP transitions align with earlier high-pressure experiments and firstprinciples computations, indicating the validity of our MD findings. Thus, the findings reveal novel atomistic insights into stress-induced phase stability in aluminium, with implications for fatigue resistance and microstructural design.

Aluminum and its alloys, such as Al–15Fe, Al–10Fe, and Al–5Fe, possess a unique blend of mechanical properties attributed to the development of intermetallic phases. These alloys are formed through the metallurgical casting process, where aluminum reacts chemically with iron. Renowned for their outstanding mechanical and physical characteristics, including corrosion resistance, high strength, thermal stability, and low density, Al–Fe intermetallic alloys find extensive applications across industries such as automotive, aerospace, chemical, medical, and electronics. This study involves the synthesis of Al–Fe intermetallic alloys through metallurgical casting using an induction furnace, supported by molecular dynamics simulations. The mechanical properties, including yield strength and hardness, were systematically assessed with varying iron content in the alloys. Results indicate a significant enhancement in these properties with increasing Fe content. Furthermore, structural phase analysis and the formation of intermetallic compounds were examined using optical microscopy and atomic-level investigations, offering a detailed understanding of the microstructural and intermetallic phase distribution within the materials.

The present investigation intends to examine how the dynamic strain aging (DSA) phenomenon affects tensile flow curves, mechanical properties, and dislocation density through tensile loading. Monotonic tensile tests were carried out at room temperature (RT) and elevated temperatures up to 400 degrees C, whereas the strain rate varied from 1 x 10_ 4 s_ 1 to 1 x 10_2 s_ 1. Several features of DSA include serrations on the stress-strain curve, negative strain rate sensitivity, an increase in ultimate tensile strength, and a decrease in ductility with an increase in the temperature of the tensile test. DSA phenomenon was quite evident in a temperature range of 200-350 degrees C at all the strain rates; nevertheless, the dominant DSA temperature regime was observed between 250 and 300 degrees C for a slow strain rate of 1 x 10_ 4 s_ 1. However, an increase in the strain rate, the dominant DSA was observed at increased test temperature. Transmission electron micrographs taken post-tensile test revealed that the test conditions that showed a dominant DSA behavior have a higher dislocation density as compared to conditions where there was insignificant or no DSA. The dominant DSA and non-DSA tensile tested specimens had dislocation densities of 12 x 1015 m_ 2 and 5 x 1015 m_ 2, respectively. The shift of dominant DSA phenomena was explained with the help of dislocation waiting time at local barriers and diffusion time of solute atoms at the test temperature.

Achieving isotropic mechanical properties in Al–Cu–Li alloys is critical for next-generation aerospace structures, yet remains challenging due to complex interactions between deformation textures and precipitate distributions. This study systematically investigates the effect of strain path variations—unidirectional (CP-I) versus non-unidirectional (CP-II)—on microstructure, texture evolution, and mechanical anisotropy of AA 2199 sheets processed via cold rolling, solution treatment, and aging (ST-AA). True von Mises strains corresponding to 60 ε̅ = 0.75, 1.17, 1.88) were employed to quantify deformation effects. The CP-IISTAA route at 75 varepsilon = 1.17) produced fine, equiaxed grains (13–20 μm), dominant ND rotated cube texture (volume fraction ≈ 18

The increasing demand for fuel-efficient and lightweight vehicles has driven the development of advanced-high-strength steels (AHSS), particularly for electric vehicle (EV) applications. In this study, the microstructure and mechanical properties of a 3.5 wt.

Molecular dynamics simulation methodology is widely used to explore numerous properties of engineering materials. This methodology is very economical and provides in-depth atomic information of materials properties like mechanical, thermal, electrical, corrosion properties, etc. In this study, a method called large-scale molecular dynamics simulation was used to look at the tensile and creep properties of a single-crystal Fe-Cr-Ni alloy. Many elements of physical metallurgy such as atomistic structural changes and dislocation activity during tensile and creep deformation have been explored. The adaptive common neighbor analysis (aCNA) and potential energy (PE) evolution have all been used to describe the atomistic placement of the Fe-Cr-Ni alloy during tensile deformation. The main results of this study could help us fully understand the atomic mechanical properties of different types of steel and similar alloys. This has helped improve the performance of engineering metals.

Molecular dynamics (MD) simulation was used to investigate the effect of different temperatures and strain rates on mechanical properties of Fe–Cr–Ni alloys. This methodology is very cost-effective and provides detailed insight through atomic information about uniaxial tensile behavior of Fe–Cr–Ni single-crystal alloy. Phase transformation under various strain rates and temperature conditions can be studied using MD simulation. In this paper, we have worked on the uniaxial tensile deformation of Fe–Cr–Ni alloy at various temperatures and strain rates by using large-scale molecular dynamics simulation (LAMMPS) methodology. Mechanical properties like yield strength, tensile strength, and Young’s modulus have been investigated at various temperatures and strain rates. Atomistic structural changes, formation of stacking faults due to straining effects, and temperatures on Fe–Cr–Ni alloy have been investigated. Adaptive common neighbor analysis (ACNA) was utilized in this simulation to characterize the atomistic arrangement and phase transformation of the Fe–Cr–Ni alloy using energy changes during uniaxial tensile deformation. Therefore, this investigation’s significant results provide comprehensive knowledge of changes in the mechanical properties of steel and other alloys at different strain rates and temperatures for various industrial applications.

Polymer matrix composites (PMCs) are consisting of reinforcing fillers embedded into polymer matrices. Nowadays, PMCs are widely used as structural materials and replacing the traditional materials. These are used in automotive, railways, missiles and marine industries, defence, aerospace and other applications. Because of the increasing demand for lightweight, corrosion and chemically resistant as well as electrically insulating and high flame retardant materials, the global composite market is growing at a Compound Annual Growth Rate (CAGR) of 4.1% from 2018 to 2023. This chapter describes the information regarding the reinforcing fillers and matrices (both thermoplastics and thermosetting) as well as the composite manufacturing processes and applications. Polymer nanocomposites are also discussed. This chapter also includes a special topic of self-healing composites including its prospects and technological demand.

In this paper, cold metal transfer (CMT) welding-brazing of automotive grade dual phase steel with Al 5052 alloy using ER 4043 filler wire was studied. The present work objective is to discuss about the influence of different process parameters such as wire feed rate (WFR) and generated heat input on joint quality and microstructure of the dissimilar metal and to predict the current-voltage characteristics to analyse process stability of the process. The Cyclogram and current-voltage transient graphs exhibit the stability of the CMT process, suitable for joining dissimilar metals like Al and steel. The mechanical and microstructural properties of an overlap joint were examined by using shear-tensile test, microhardness test and metallographic technique. At WFR 5 m/min and torch position 0.6 mm, the highest failure load of 4.0 kN was achieved due to the better wettability of molten filler on base metal and increased interfacial area of deposited bead. The microstructure shows the variation in the intermetallic (IM) layer at different WFR and the zinc accumulation at the toe of the bead. The microstructural morphology and EDS analysis show the presence of hard and brittle Al-Fe-Si ternary phases and IM layer at the brazing interface of the joint. In addition, spillage, and clusters of needle-shaped IM phases into the bead were also seen due to the high turbulence in the weld pool when WFR increased. Variation in IM layer thickness and zinc accumulation was also observed in microstructural analysis of the bead and joint. Failure load increased initially while raising the WFR but then decreased at torch position of − 0.6 mm at WFR 5 m/min despite an increase in wettability, it was due to the presence of hard and brittle IMCs and cracks developed in the IMC layer due to the residual stress and solidification shrinkage.

The evaluation of mechanical properties, microstructure, and phase transformation of Fe-Cr-Ni alloy under different strain rates, at temperature 300 K has been done in this investigation, using molecular dynamics simulation. These properties are of utmost importance, for the design and development of different grades of metals and alloys. In this study, a nano-size face center cubic (FCC) single crystal of Fe-Cr-Ni alloy has been selected to examine stress–strain response under various strain rates at room temperature through molecular dynamic simulation. In this simulation study, It was found that, the evolution of an alternate multilayer stack of a rectangular block of face center cubic (FCC) atoms, hexagonal close pack (HCP) rectangular block atoms and strain induced martensitic phase transformation occurred during uniaxial loading at a strain rate of 1011 s−1 at ambient temperature. It was also observed that the intersection of stacking faults is a source of dislocation. This study based on MD simulation provides an in-depth concept of the mechanical properties during mechanical and thermal processing. It also helps improve the mechanical properties of various grades of steel and other engineering materials.

This investigation aims to examine the effectiveness of torch position, welding-brazing parameters on the embedded bead profile and load carrying potential of the brazed joint of zinc coated DP600 steel and Al 5052 joined by cold metal transfer (CMT) technique. The base metals were joined at different torch position (-0.6, 0 and 0.6 mm) in lap joint position using Al-based filler wire. At different wire feed rate (WFR) 3, 4 and 5 m/min changes in bead shape and its geometry were observed. The various modes of failure were classified based on effective bonding length (LH-LV) and LH/theta ratio. The best combination of welding-brazing parameters at which the maximum load bearing capacity of 4.1 kN and enhanced bead properties was achieved at 0.6 mm torch position and WFR 5 m/min. The intermetallic compound layers formed during the process affect the tensile properties of weld-brazed joint. The possible intermetallics and the presence of major elements in intermetallic layer were analyzed by energy-dispersive X-ray spectroscopic analysis. Furthermore, in this investigation, it was also observed that the thickness of IMC layer increases with the increasing WFR and heat input up to a critical value of 10 mu m.

In automobile industries production of lightweight vehicles to increase the performance of a vehicle, reduction in fuel consumption, and the low emission of toxic gases have generated the need for the fabrication of multi-material design. In recent years an effort was made to fabricate the automobile bodies with dissimilar metals like aluminium and stainless steel but welding or joining of these two different metals is very difficult due to non-identical thermo-physical properties, melting point, zero solubility, and the emergence of hard and brittle intermetallic compound (IMC) and phases at the interface of joint. Different welding and joining processes were attempted to join steel and aluminium to restrict the emergence and growth of hard and brittle IMC phases and their layer thickness at the interface through effective heat control input. Though MIG, CMT-MIG brazing is more effective than any other welding and joining processes due to their control on heat supply and synchronized transfer of molten metal. This study aims to examine the several welding factors in the joining of steel and aluminium by MIG, CMT, and other arc-based welding methods. Various factors such as the impact of heat input, process parameters, and different filler wires on the formation of IMC thickness and firmness of joint are analyzed and discussed.

Medium-Mn steels are one of the potential advanced high strength steels (AHSS) of third-generation, having an exceptional combination of high strength-elongation and crashworthiness. They have Mn in the range of 3–12 wt.% and consist of so-called “ultrafine-grained (UFG)” equiaxed or lath-like ferrite/martensite and retained austenite microstructure. The retained austenite content and its stability play a dominating role in influencing the properties of medium Mn steel as it delays the fracture or failure of the steel during deformation or event of a crash, via strain hardening mechanisms like “Transformation Induced Plasticity (TRIP)” and “Twinning Induced Plasticity (TWIP)” effects. The retained austenite amount and its stability can be tuned by adopting an appropriate intercritical annealing schedule, as it is influenced by various factors like the elemental composition of austenite, its grain size, morphology, etc. This article illustrates the evolution of medium-Mn steel, its microstructure, properties, and model for optimizing the retained austenite fraction, and factors influencing it.

Medium manganese steel is a 3rd generation advanced high strength steel, which contains 3–12 wt% manganese. This steel is highly suitable material for the automobile industry due to good balance between the cost of material and the tensile properties. It has got the optimum amount of strength and elongation. Initially the microstructure of this steel after cold rolling is deformed martensite (ά). Intercritical annealing is done to get moderate amount of retained austenite (γr) having good stability, which leads to higher strength and better ductility due to transformation-induced plasticity (TRIP). The formation of stable retained austenite (γr) by intercritical annealing process is our prime interest. Medium Manganese steel usually exhibits austenitic-ferrite microstructure after the intercritical annealing process, which makes the steel suitable for 3rd generation advanced high strength steels as this microstructure gives good amount of elongation. From this study we get best combination of intercritical annealing and quenching to get the required microstructures and properties. Thermo-calc software is used to find the optimum temperature for intercritical annealing at which we get optimum amount of retained austenite (γr) containing maximum manganese. Tensile tests were carried out at different pre-strain level from the samples taken in both rolling and transverse directions. Samples were prepared for SEM and optical microscope characterization to see the changes from initial microstructure of the steel. X-ray diffraction was also done to find out the amount of retained austenite that we are getting from tensile sample after pre-strain it to different level. It was concluded that after intercritical annealing at 650 °C for 2 h the steel sample have approximately 22% retained austenite and ultimate tensile strength (UTS) of 843 MPa and total elongation of around 36%.

SA333 Gr-6 steel is a candidate material for the primary cooling system in nuclear power plants. During service, piping components experience asymmetrical stress or strain cycling, resulting in plastic strain accumulation and a drastic reduction in fatigue life compared to symmetrical loading. This investigated steel is prone to the dynamic strain aging phenomenon. The present investigation deals with DSA and its influence on ratcheting deformation. Ratcheting tests were conducted at fixed load (σm = 50 & σa = 400 MPa) with varying temperatures from room temperature to 350 °C and stress rates (20-700 MPa s−1). Result reveals that the steel shows greater resistance to ratcheting strain and increased fatigue life at DSA dominant temperature regimes. The DSA is active at a temperature between 250 and 350 °C and the DSA regime gets shifted to a higher temperature with the increase in stress rate. Transmission electron microscopy (TEM) studies reveal severe dislocations activities and dislocation forest at DSA dominant specimen, whereas the arrangement of dislocations into well-developed cell structures at the non-DSA regime. TEM result is corroborated by calculating dislocation density from x-ray diffraction analysis, and it was found greater dislocation density at DSA dominant and lower at the non-DSA regime.

Drilling process is used to make hole on engineering materials. Performance characteristics after drilling process such as surface quality and dimensional errors are used for enhancing the assembly accuracy. Minimization of these errors are difficult task and challengeable. In this work, an attempt of drilling process on Aluminum Metal Matrix composite (Al-MMC) and these errors are analyzed. The process parameters are optimized using Multi Objective Optimization by Ratio Analysis (MOORA) method. The result of the work revealed that errors after drilling process are minimized using optimized process parameters. MOORA method is a simple method to execute optimize the process parameters.

In piping structures, the low cycle fatigue loading arises from thermally induced strain cycles associated with start-up and shut-downs and fluctuation in loading conditions. SA333 Gr-6 steel is prone to dynamic strain aging (DSA) and the parameters that govern the DSA are temperature and strain rate. There are limited studies on DSA in the investigated steel. In the present investigation, fatigue experiments were conducted at a fixed strain amplitude of +/- 0.5 % with the variation of temperatures (RT to 400 degrees C) and strain rates (1 x 10(4) s(-1) to 1 x 10(-2) s(-1)). The results reveal that the cyclic deformation behavior depends on temperatures and strain rates. The steel shows cyclic hardening characteristics at elevated temperatures which indicates the occurrence of the DSA phenomenon. The negative strain rate sensitivity and temperature dependency of stress amplitude are the manifestations of DSA. The present study shows the deleterious effect of DSA on fatigue life. The DSA temperature regime found in the temperature 200-250 degrees C for 1 x 10(4) s(-1) strain rate, 250-300 degrees C for 1 x 10(-3) s(-1) strain rate, and 250-350 degrees C for 1 x 10(-2) s(-1) strain rate. The DSA regime gets shifted to a higher temperature with the increase in strain rate. Transmission electron microscopy investigations reveal that the fatigue failed specimen at the DSA regime shows severe dislocation activities and dislocation tangles, whereas minor dislocation activities and cell structures were observed at the non-DSA regime. The dislocation density calculated from the X-ray diffraction analysis was higher at DSA compared to the non-DSA regime.

The aim of this investigation is to study the influence of temperature on the cyclic plastic deformation behavior of SA333 Gr-6 steel at two loading conditions. Strain-controlled cyclic loading experiments were carried out at ± 0.5% total strain amplitude, 1×10-3 s-1 strain rate, and temperature varied from RT to 400°C, whereas stress controlled ratcheting experiments were conducted at fixed mean stress (σm) of 50 MPa and stress amplitude (σa) of 400 MPa, 115 MPa s-1 stress rate, and in the temperature range of RT to 350°C. The investigated steel shows cyclic hardening characteristic at DSA temperature regime in both the loading condition. The steel shows lower fatigue lives at 250°C and 300°C temperatures even though plastic strain amplitude is smaller. The ratcheting life of the steel increases and strain accumulation decreases with the increase in temperature up to 300°C and on further increment in temperature ratcheting life get decreased. The steel shows greater cyclic hardening at both the loading conditions at 300°C.