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Laser-based surface enhancement techniques improve metals’ mechanical properties. Laser Hardening (LH) and Laser Shock Peening (LSP) techniques are effective particularly well with low-alloy steel made of 34Ni-Cr-Mo6, which is a type of steel alloy that is put to use in a wide variety of fields because it possesses excellent levels of both strength and toughness. For specific applications, the laser can be shaped into line or spherical beams. On the other hand, typical industrial requirements of low alloy steel components like 34Ni-Cr-Mo6 are enhanced hardness and mechanical strength with minimum or no distortion. A 3 kW high power fiber laser with a flat top-hat beam of dimension $30\times 1$mm and a circular beam of Ø6mm are employed in this study. Investigation into the effects of repeated LSP on the microstructures and residual stress of 34Ni-Cr-Mo6 low alloy steel was also done. LSP treatment is carried out at 6.36GWcm${}^{-2}$ Laser Power Density (LPD) with different laser impacts, i.e. single and double, by keeping 0% overlap along the scanning direction and perpendicular directions, respectively. The shock-peened samples were characterized in terms of residual stress measurements and microstructural evolution using different characterization techniques. A substantial improvement in compressive residual stress was observed at the hardened cross-section i.e. $\sim -260$MPa and at shock peened surface $\sim -620$MPa respectively as compared to the as-received sample ($\sim -100$MPa). LH samples showed a better result in terms of microhardness values when compared to shock peened samples i.e. for LH, the microhardness values at the cross-section were $\sim 710\pm 40$HV${}_{0.5}$ nearly 2.5 times increase in hardness. Extreme plastic deformation was found by microstructural examination of cross-sections of LSP-treated areas. Hardness was nearly marginally improved in multiple times LSP-treated samples compared to unpeened ones as a result of LSP.

This work presents a comprehensive investigation into the microstructural and tribological properties of Al6061 alloy composites reinforced with E-glass fibers and soda–lime particulates, both before and after Equal Channel Angular Pressing (ECAP) processing. The study explores the intricate relationships between reinforcement materials and the aluminum matrix, shedding light on their collective impact on material behavior. Elemental composition analysis via Energy Dispersive X-ray (EDX) reveals crucial elements shaping the properties of these composites, highlighting the dominance of aluminum in the matrix and the contributions of silicon, calcium, sodium, and oxygen from the reinforcement materials. Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) demonstrate refined grain structures, improved reinforcement dispersion, and enhanced interfacial bonding post-ECAP, indicating potential for superior mechanical properties. Furthermore, wear test analysis on these composites, encompassing varying reinforcement percentages and load conditions, unveils consistent trends in wear behavior. Higher reinforcement percentages, particularly with E-glass fibers, lead to reduced specific wear rates, showcasing enhanced wear resistance. Post-ECAP results consistently exhibit lower wear rates, highlighting the positive impact of ECAP on wear resistance. Statistical analysis using Taguchi and Analysis of Variance (ANOVA) techniques underscores the critical role of reinforcement percentage in wear characteristics, with optimal configurations identified for both E-glass fiber and soda–lime particulate composites. These findings offer valuable insights for designing and optimizing materials, emphasizing the importance of reinforcement levels, load, and speed in enhancing wear resistance and optimizing material performance for specific applications.

Recently friction stir processing (FSP) has emerged as an effective tool for enhancing metal properties through microstructure modification. FSP is a solid-state process where the material within the processed zone undergoes intense plastic deformation resulting in dynamically recrystallized grain structure. This research demonstrates the use of FSP for creating ultrafine grained materials through severe plastic deformation. FSP was applied to extruded 6082-T4 aluminum alloy to produce ultrafine grained microstructure with grain sized from 0.5 to 3μm. The hardness of the FS processed 6082 aluminum alloy increased significantly with decreased tool rotation speed.

Effect of deformation induced transformation (DIT) process on ferrite grain size and ferrite transformation volume fraction in the refractory low alloy steel 12Cr1MoV by controlled rolling and controlled cooling technology were experimentally studied. Simulation experiments of hot deformation were carried out with the Gleeble-1500 system. Single-pass and multi-pass hot rolling process with different deformation temperature, deformation reduction, strain rate and cooling rate were performed separately. The ferrite grain size decreased and the ferrite volume fraction increased with decreasing deformation temperature, and the extra-fine ferrite grain about 1.01µm was obtained when the deformation temperature reached 780°C. Higher deformation reduction resulted finer ferrite grain size and higher ferrite volume fraction. Both the ferrite grain size and ferrite volume fraction decreased with increasing strain rate. The ferrite grain size decreased but the ferrite volume fraction didn't change much when the cooling rate increased. The grain size and the ferrite volume fraction were improved more by three-passes than two-passes rolling. The mechanism of grain refinement by DIT was discussed.

Experiments and numerical simulations were conducted to investigate flow behaviour of the specimen made of commercially pure aluminum alloy (AA1050) during multi-pass equal channel angular pressing (ECAP) for route A up to four passes. Influence of processing conditions on friction and flow behaviour was investigated by measuring load variations, microhardness distributions and microstructure changes depending on the number of passes. It was carefully simulated by employing the finite element technique by tracing the local deformation, determining the load requirement and comparing the local strain with microhardness distributions. Change of the grain size depending on the number of passes was monitored by transmission electron microscopy. The present work clearly showed flow characteristics of the deformed specimen at the central and surface regions due to the effect of the number of passes for the multi-pass ECAP.

${\mathrm{\text{Bi}}}_2{\mathrm{\text{Sr}}}_2{\mathrm{\text{Co}}}_2{\mathrm{\text{O}}}_y$ ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit $(ZT)$ of ${\mathrm{\text{Bi}}}_2{\mathrm{\text{Sr}}}_2{\mathrm{\text{Co}}}_2{\mathrm{\text{O}}}_y$. The optimum $ZT$ value of 0.26 is achieved at 923 K by the third sintered sample.

Bi₂Te₃ is a classical thermoelectrical material and has been applied widely in commerciality. In this paper, the influence of La₂O₃ dispersion as the nanosecond phase on the thermoelectric properties of Bi₂Te₃ was investigated. The Bi₂Te₃ nanopowders were prepared by the hydrothermal method. After adding the La₂O₃ nanopowders according to Bi₂Te₃ + $s$ wt% La₂O₃ ($s=0$, 0.5, 1.0, 1.5), they were hot pressed into bulks in vacuum. The experimental results showed that the dispersed La₂O₃ as the nanosecond phase could enhance phonon scattering and suppress the thermal conductivity of Bi₂Te₃ effectively. Although their electrical resistivity increased due to the deteriorated carrier mobility, as a combined effect, the thermoelectric merit value (ZT) of the Bi₂Te₃ + 0.5 (or 1.0) wt% La₂O₃ was optimized and reached 0.61 at about 455 K.

Recent developments in the field of manufacturing techniques and alloy development of light materials are reviewed. In the field of manufacturing Aluminium based components, special attention is given to casting, including liquid forging and semi-solid forming technology while for sheet metal forming technology the focus is on material properties and process technology in superplastic forming. For the manufacturing of Magnesium-based components, special attention is given to casting processes and alloy development for casting. For wrought Magnesium, material properties control is covered. For Titanium-based components, an overview of the latest additions to high strength alloys are given, including non-linear elasticity as demonstrated by materials like GUM Metal™. Advanced forming technology such as Levi Casting are also treated.

Different amounts of Al-5Ti-1B master alloy (TiBAl) were added to the AZ31 magnesium alloy (Mg-3Al-1Zn-0.2Mn) as grain refiner and the resulting microstructure and grain size distributions were studied after extrusion and equal channel angular pressing (ECAP). Results showed that the addition of 0.6% TiBAl had the strongest grain refinement effect, reducing the grain sizes by 54.5 and 48.5% in the extruded and ECAPed conditions, respectively. The observed grain refinement was partly due to the presence of the thermally-stable micron- and submicron-sized particles in the melt which act as nucleation sites during solidification. During the high-temperature extrusion and ECAP processes, dynamic recrystallization (DRX) and grain growth are likely to occur. However, the mentioned particles will help in reducing the grain size by the particle stimulated nucleation (PSN) mechanism. Furthermore, the pinning effect of these particles can oppose grain growth by reducing the grain boundary migration. These two phenomena together with the partitioning of the grains imposed by the severe plastic deformation in the ECAP process have all contributed to the achieved ultrafine-grained structure in the AZ31 alloy.

High Si bainitic steel has received much interest because of combined ultra high strength, good ductility along with high wear resistance. In this study, the microstructural evolution of dual phase bainitic ferrite-austenite steel after heavy compression was investigated. Compression tests were conducted at temperature of 298K on the rectangular billets at the strain rate of 0.001s_-1. The samples were deformed to 40% and 70% of their original thickness. The EBSD results show formation of nano grains with high angle grain boundaries through 70% compression, which confirms grain refinement. Additionally, 40% deformation resulted in enhancement of the dislocation density and formation of subgrains at ferrite unites. Also, it was found during 70% compression of the steel, the austenite transforms to the martensite, which is in agreement with thermodynamic calculations.

Nano/Submicron crystalline grains of about 250 nm were obtained in a metastable austenitic stainless steel AISI304L by an advanced thermomechanical process consisting of heavy conventional cold rolling and annealing. Effects of cold thickness reduction and temperature and time of the reversion treatment on microstructure and mechanical properties of the steel were investigated. The nano-structured austenitic steel exhibited not only high strength (above 1 GPa) but also good elongation (above 50%).

The solidification microstructure of cast SiC particles reinforced magnesium composite has been studied using optical and transmission electron microscope (TEM). Metallographical examination showed that the grain size of magnesium composite was much smaller than that of unreinforced magnesium alloy. In the mean time most SiC particles were pushed and segregated at the grain boundaries while few SiC particles were entrapped in the magnesium grain. The primary magnesium phase which heterogeneously nucleated on the SiC particle surface has been identified with a small lattice disregistry (2.3%) while their crystallographic orientation relationship was . Finally, the grain refining mechanisms in SiC particles reinforced magnesium composite have been proposed.

The effects of different initial condition (as-cast, homogenized) on grain refinement strengthening of AZ31B magnesium alloy were investigated by optical microscopy and tensile testing. The results show that the inhomogeneous second-phase γ-Mgl7Al12 along the grain boundary in as-cast was still distributed unevenly after extrusion. Compared with as-cast, tensile strength of homogenization was increased greatly after extrusion. At 250°C and extrusion ratio of 50, tensile strength reached to 391Mpa and elongation of 15.2%.The grain size after extrusion is bigger than that of as-cast after extrusion, so the Tensile strength is lower than that of as-cast. Besides, non-equilibrium phase γ-Mgl7Al12 has been dissolution after homogenized and grain distributed uniformly. Therefore, plasticity was improved greatly at the same condition as upon.