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In this paper, a forging tool of a new design is proposed, which allows to implement shear and alternating strain in the entire volume of the deformed billet with a smaller change in its initial dimensions. To confirm the effectiveness of the proposed new forging tool in obtaining billets and forgings of the plates and slabs type of the required quality, a laboratory experiment was conducted. During the laboratory experiment, the forging of billets made of the steel 45 was carried out in such forging tools as step-wedge dies of two different variants (proposed and previously known) and in step dies. Analysis of the shape change of billets and the evolution of the microstructure of steel after two deformation cycles showed that the use of the step-wedge dies with a wedge protrusion on the upper die and a wedge cavity on the lower die is more promising for forging billets and forgings of the plates and slabs type with a given level of mechanical properties, since it allows to obtain a fine-grained structure with a smaller change in the initial dimensions of the billet. [ABSTRACT FROM AUTHOR]

Structural automotive components are extensively made of aluminum alloy forgings, due to the elevate strength and low weight required. These products are frequently subjected to recrystallization. Recrystallization, often limited to surface or forging portions, is expected to reduce its tensile strength and corrosion resistance, but the literature is scarce on this subject. For a more comprehensive understanding, the present research studied the corrosion behavior of samples collected from EN AW 6082‐T6 forged components, designed to expose both recrystallized and not recrystallized surfaces to the corrosive environment. Several standardized corrosion tests (i.e., PV 1113, ISO 11846, and VW 96380) were applied to assess the most representative with respect to real field exposure. Tensile tests were performed in four different conditions, recrystallized and not recrystallized specimens in an as‐forged state or after corrosion. The recrystallization led to a reduction in tensile properties, but this gap was compensated by a higher corrosion resistance than the not recrystallized samples. Consequently, the mechanical properties became comparable after the corrosion test. [ABSTRACT FROM AUTHOR]

The present study systematically investigated the influence of forging strategies on the microstructures and deformation behaviors of a Ti–5Al–5Mo–5V–1Cr–1Fe (Ti-55511) near β-titanium alloy. Microstructure analysis revealed that the as-cast alloy exhibited a basket-weave structure predominantly comprised of lamellar α phase. Three different forging methods were used to adjust the morphology of the primary α phase during the final two forging steps: 1) dual-phase (825 °C) + dual-phase forging (DD sample), 2) dual-phase + β single-phase (900 °C) forging (DS sample), and 3) β single-phase + dual-phase forging (SD sample). After standard heat treatment, the DD samples exhibited equiaxed αp due to sufficient deformation in dual-phase region, while DS samples transformed into lamellar shape due to αp reforming during the cooling process of the final β single-phase forging. In contrast, the SD samples displayed short-rod αp due to reforming in the single-phase region and insufficient deformation in the dual-phase region. All these αp and βt phases can hinder dislocation motion to enhance the strength. The DS sample exhibited the best combination of strength, ductility, and impact toughness. During tensile deformation, planar dislocation slip and {101‾1} twinning were dominant in the αp, while wave slip occurred in the βt phase. The fracture behavior transitioned from brittle to ductile after forging and heat treatment. Overall, this study offers a practical and effective method for optimizing the mechanical properties of the Ti-55511 alloy.

In this study, CuCr50 alloys were prepared by aluminum thermal reduction-high frequency refining process, and the properties were improved through hot forging and heat treatment. With increasing deformation, large Cr particles were spheroidized and refined, significantly improving the performance of the alloy. When the deformation exceeds 27%, the conductivity reaches 17.73 MS/m, the hardness reaches 116.5 HB, and the density reaches 7.91 g/cm3. After solution at 975 °C for 1h and aging at 550 °C for 4h, the conductivity of the CuCr50 alloy further increased to 19.63 MS/m, the hardness reaches 121.5 HB. Compared with the as-cast alloy, the conductivity, hardness and density are increased by 71.07%, 18.81% and 2.99%, respectively. In the 5% deformed CuCr50 alloy the precipitates of nanoscale Cr particles formed a co-lattice with the copper matrix. In the 14% deformed CuCr50 alloy, nanoscale Cr particles precipitated and dispersed in the Cu matrix, and the relationship between the precipitated Cr phase and the Cu matrix was incoherent. The amount of precipitated Cr phase in the 27% deformed CuCr50 alloy had a semi-coherent relationship with the Cu matrix, the orientations of Cu(2‾00)//Cr(110). The hardness enhancement is mainly attributed to grain refinement and density increase, and the conductivity enhancement is mainly attributed to Cr particle precipitation after aging treatment.

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The main objective of the present work is to produce AlxCoCrFeNiMo0.5 alloy through a wrought process. AlxCoCrFeNiMo0.5 high-entropy alloys with two different Al contents (x = 0.2 and 0.5) were prepared by vacuum arc melting followed by thermo-mechanical processing. Microstructural evolution was investigated after hot forging and subsequent homogenisation using XRD, SEM, and TEM. The final microstructure corresponding to Al0.2 and Al0.5 are BCT (sigma) in the FCC matrix and BCT (sigma) and ordered BCC together in the FCC matrix respectively. Room-temperature mechanical properties were investigated using uniaxial compression and hardness measurements. There is an apparent increase in strength and a decrease in ductility for the Al0.5 alloy. However, a higher ductility was observed in Al0.2 alloy with a compromised reduction in strength. [ABSTRACT FROM AUTHOR]

The results of the study of the influence of multi-axial isothermal forging on the microstructure and martensitic transformation in a Ni58Mn18Ga24 alloy have been presented. Forging is performed in two stages: the first stage is forging at 700°C by four passes with true strain e ≈ 1.64; the second stage is forging at 500°C by one pass with e ≈ 0.24. The forging deformation results in the transformation of the original equiaxed-grain structure. No new grains are formed after the first stage of treatment. New recrystallized grains in a very negligible extent begin to be observed only after the second stage of deformation. Probably, at the first stage, the mechanism of fragmentation of the grain structure is not started due to an insufficient density of defects upon the deformation at 700°C. The characteristic temperatures of martensitic transformation are shifted after forging to the low temperature region. The anharmonic change in the sample length is observed in the region of martensitic transformation for the both treated states. In general, this indicates a low level of defect density and internal stresses in the sample. [ABSTRACT FROM AUTHOR]

Multi axial forging (MAF) is a forging-based severe plastic deformation (SPD) technique which is prominently used to refine grain structure and improve the strength of the material. While the advantages of MAF lie in its simple tool design and ability to process bulk materials, the main limitation is the inhomogeneity in the generated microstructure across the cross-section at initial passes. Increasing the number of MAF passes may partially help to solve the problem, but arbitrary increase in the number of passes may lead to redundant increase in manufacturing cost and time. The current work proposes a manufacturing strategy for MAF to achieve homogeneous microstructure with uniform grain refinement by using reduced number of MAF passes. To achieve structural uniformity within fewer MAF passes, a controlled thermo-mechanical based optimum MAF process strategy is developed on a commercial pure Al through the finite element analysis (FEA) simulation and the same is validated experimentally. The manufacturing strategy resulted significant grain refinement via simultaneous action of continuous dynamic recrystallization and geometric dynamic recrystallization with microstructural homogeneity which caused a significant improvement in tensile properties (more than two times than the base) with considerable ductility (more than 25%) and isotropy property across the thickness. The scientific knowhow has been established via processingestructureeproperty correlation-ship. [ABSTRACT FROM AUTHOR]

This paper presents results on the microstructure and mechanical properties of a new low-cost titanium alloy Ti-5Al-1.5Mo-1.8Fe after different forging processes. The β phase transformation temperature of this alloy was 950 °C. In this study, the forging temperatures were designed at 920 °C and 980 °C, and the deformation degree ranged from 20% to 60%, with an interval of 20%. This study investigated the impact of the equiaxed α phase and shape of the lamellar microstructure on the tensile characteristics and fracture toughness of an alloy. The research employed a microstructure analysis and static tensile testing to evaluate the effect of forging temperatures and degree of deformation on the microstructure features. The findings revealed that forging temperatures could modify the microstructure characteristics, and the degree of deformation also affected this microstructure. This study demonstrates that a bimodal structure with an equiaxed α phase can be utilized to balance high strength and high ductility, resulting in better overall mechanical properties. [ABSTRACT FROM AUTHOR]

In our previous works, the effects of forging and heat treatment variables on microstructure evolution and mechanical properties have been studied for an ingot-metallurgy Re-bearing nickel base superalloy. To overcome the issues associated with the production of large-scale ingots and fine-grained workpieces, in the present work, the effect of hot forging and heat treatment variables was studied in a Re-bearing nickel base superalloy prepared via powder metallurgy. The purpose of the study was to reach the properly balanced mechanical properties for the potential use of the superalloy as a disc material. The initial as-HIPed workpieces were subjected to different hot forging and post-forging heat treatment or only to heat treatment (no forging). For the processed workpieces, the recrystallization behavior, size, morphology and volume fraction of γ′ precipitates were evaluated by scanning electron microscopy followed by a study of mechanical properties. The most properly balanced mechanical properties (strength, ductility, creep resistance and creep rupture lifetime) were reached for the γ grain size of dγ ≈ 13.6 µm. A finer and coarser γ grain size (down to dγ ≈ 2.6 and up to dγ ≈ 37.5 µm) even when superimposed with a higher volume fraction of dispersed secondary γ′ precipitates (in the case of dγ = 27–37.5 µm) was associated with worse mechanical properties. [ABSTRACT FROM AUTHOR]

This research studies the hot deformation behavior of cast and extruded AZ80 magnesium alloys for forging applications. Uniaxial hot compression tests were carried out at a temperature of 400 °C and strain rates ranging from 0.001 to 0.1 s−1, to various strain levels up to a true strain of 1. Detailed microstructure and texture characterizations of the deformed samples were performed using electron backscatter diffraction and x-ray diffraction techniques. The results show that multiple dynamic recrystallization (DRX) mechanisms were simultaneously active in both starting materials at all the tested deformation conditions, resulting in significant grain refinement. Cast and extruded samples showed the development of a similar microstructure, texture, and flow stress by a strain of 1, despite having very different starting microstructures. This was investigated by considering differences in DRX mechanisms and kinetics, and relative deformation mode activities. Since industrial forgings typically involve strains much higher than 1, comparable final microstructure and texture are expected in industrial-scale forgings of AZ80 at 400 °C, irrespective of the starting material state. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of the forging process of round cross-section blanks in a new design crossing strikers, which ensures the additional shear deformation implementation in the entire volume of the deformable workpiece during the deformation process. This contributes to a better closure of internal defects and a more intensive and uniform processing of the initial metal structure compared with forging in the previously known design of crossing strikers, as well as compared with forging in conventional cut-out strikers. Moreover, the presence of an additional block of cut-out inserts in this design of crossing strikers allows to obtain forgings with an even cross-section, close to a circle, without additional processing of the forgings obtained in the cut-out strikers. [ABSTRACT FROM AUTHOR]

Conventional forging followed by dual heat treatment (near-b and two-phase field heat treatments) is a feasible technique aimed at obtaining tri-modal microstructure in near-a titanium alloys. In view of the enlargement and integration of aerospace structural parts as well as the microstructure diversification of original billet, the Tie6242S alloy specimens with three different initial microstructures were subjected to multi-pass conventional forging and dual heat treatment. The flow behavior and microstructure evolution of material were analyzed. The results indicated that lamellar a has a stronger ability to coordinate deformation than equiaxed a. The more lamellar a in the microstructure, the slower the microstructure reconstruction during deformation interruption. It is feasible to obtain tri-modal microstructure by any pass conventional forging and dual heat treatment for the initial equiaxed or duplex microstructure, and two passes are more appropriate. The difference between initial equiaxed and duplex microstructures is gradually eliminated through a series of microstructure evolutions during the subsequent heat treatment. For initial lamellar microstructure, a kind of microstructure with multiscale equiaxed a can be formed after multi-pass conventional forging. The spheroidization fraction of lamellar a is significantly increased with the increase of deformation pass. Tri-modal microstructure can be obtained through three-pass forging and dual heat treatment. [ABSTRACT FROM AUTHOR]

As a material forming method, cold forging is preferred due to the reasons like absence of a heating step and high surface quality. Recently, the finite element method (FEM) has received growing attention for controlling and predicting final material properties for cold forging applications. FEM combines microstructure evolution models with failure criteria, thus providing solutions to complicated problems in the modern cold forging industry. The fastener industry extensively utilizes cold forging, in which manganese and boron-containing steels like 27MnB4 can be formed to obtain high mechanical properties. The current study investigates the effect of two different heat treatments, namely softening and spheroidizing annealing, on the formability of 27MnB4 bolts. Softwares such as Thermo-Calc 2022a and Forge NxT 3.2 were used to predict the microstructure of the wire rod and evaluate the cold forming process of the same rod under two different heat treatment conditions. Therefore, the current study also provides a relationship between microstructural features and the cold formability of 27MnB4 steel. The microstructure of 27MnB4 is predicted by CCT diagrams. The predicted microstructure corresponds to the microstructure of 27MnB4 samples taken from the production line. In addition, temperature, von Mises stress, and equivalent strain distributions for 27MnB4 steel in the hot rolled state were calculated higher than in annealed states due to the differences in the microstructure. These results demonstrate that computational material engineering methods and simulation techniques could be practical tools for cold forming processes. [ABSTRACT FROM AUTHOR]

Nowadays, great efforts are being made to develop bcc-superalloys for medium- and high-temperature applications. However, the high brittle-to-ductile transition temperatures (BDTT) have restricted their application. Therefore, designing hot-processing routes to obtain a refined grain in these new superalloys is required. Particularly in the Fe-10Al-12V (at%) alloy, we have recently tested the BDTT shifting and, using physical models, it was indicated that a combination of L21-precipitate sizes with small grain sizes could shift the BDTT below room temperature. Here, we will present the study that allowed us to design the processing route for grain refinement in the tested superalloy. Molds of different geometry and with metallic and sand walls were used to test two different types of casting. Carbide conditioning treatments for improving the sizes and distribution were studied. The recrystallization process was explored first by hot rolling and post-annealing in stepped geometry samples with two different columnar grain orientations. Finally, we analyzed the grain microstructure obtained along a hot processing route consisting of carbide conditioning treatment, forging into a squared bar, and hot rolling up to a 2.8 mm thickness strip. [ABSTRACT FROM AUTHOR]

The influence of the forging process of round cross-section blanks in a new designed forging tool implementing alternating deformations on the microstructure and mechanical properties of DIN 1.2542 steel was studied. The research results show that forging blanks using the proposed technology in a new forging tool, compared with the current forging technology in flat strikers, allows obtaining higher quality metal with an equiaxed fine-grained structure. [ABSTRACT FROM AUTHOR]

In this paper, a new forging technology realizing intense shear deformations during processing with a tool for its implementation was considered, and the influence of the proposed forging technology on the microstructure evolution of 7CrMn2WMo economy‑alloyed steel was revealed. A comparative analysis of the results of the microstructure evolution when forging blanks made of 7CrMn2WMo steel according to the proposed and current technologies proves the usefulness of a new design tool instead of the currently used flat strikers, since forging in the proposed forging tool provides more intensive and uniform processing of the cast structure over the entire section of the workpiece compared to forging in the flat strikers.

Hot deformation behavior of 4130 steel and optimization of its processing parameters are presented in this paper. Compression tests were performed at temperatures ranging from 800 to 1200 °C and at the strain rates in the range from 0.01 to 100 s−1. A comprehensive analysis of the material behavior at different temperature and strain-rate ranges was performed taking into account various criteria of stability and instability of the material flow under various thermomechanical conditions. The flow–stress curves obtained during compression tests, as well as the processing maps elaborated on the basis of various flow–stability criteria, are discussed. Processing parameters developed according to the Prasad's and Murty's criteria are recommended for designing the technology of forging of the investigated steel. Such parameters ensure the homogeneity and stability of the material flow in a forged part, what was confirmed by successful forging of 4130 steel in industrial conditions. The processing map developed according to Gegel's approach, as compared to the processing maps obtained in accordance with the Prasad's and Murty's criteria, should be treated as general support for determining the thermomechanical processing parameters. [ABSTRACT FROM AUTHOR]

00Cr32Ni7Mo3.5N parts were prepared by hot isostatic pressing (HIP) and forging process in this study. The effect of solution heat treatment on microstructure, mechanical properties and pitting resistance were investigated. Under solution treating at 1100°C, the phase constitution in HIP parts can be adjusted to comprise approximately 50% austenite (γ) and 50% ferrite (δ) phases with equiaxed structure, and this post-processing can meanwhile help to dissolve precipitated brittle σ phase. In comparison, the banded dual-phase structures in forged counterparts cannot be removed even after annealing at 1200°C. The desired phase proportion after solution treatment plus the equiaxed grains impart superior comprehensive performance to HIP parts with the tensile strength of 886 MPa, elongation of 48.0%, impact energy of 83 J, and pitting potential of 0.9659 V in neutral 3.5 wt-% NaCl solution. Based on this work, HIP seems to be a promising method to fabricate near-net-shape 00Cr32Ni7Mo3.5N parts. Highlights SAF3207 were prepared by HIP and was compared with its forging parts. HIP samples show equiaxed structure, while forgings are banded dual phase structures. Phase constitution can be adjusted to be approximately 50% austenite and 50% ferrite. The brittle σ phase can be completely removed after solution treatment. HIP seems a promising method to fabricate SAF3207 with high performance. [ABSTRACT FROM AUTHOR]

To improve its ductility and clarify the mechanism, the AlSi7Mg alloy fabricated by a novel casting-forging process was solid-soluted at 535 °C for 5 h, followed by aging at 170 °C for 2 h. Phase component, microstructure were observed and mechanical properties were tested. The results show that the alloy contains Al, Si and Al–Si intermetallics. The eutectic Si particles present equiaxed and the Al–Si precipitations present filamentous morphorgy in the alloy. The eutectic Si particles present quasi-continuous network distribution, dividing the matrix into equiaxed units. When the deformation degree increased from 15% to 35%, the units are refined and the precipitation of Al–Si intermetallics is prevented. The difference of ultimate strength between surface and center was decreased, while the elongation improved obviously with the increase of deformation degree. The most excellent elongation reached 12% when the deformation degree was 35%, with the improvement of 7%. The improvement of ductility is owed to the fine, equiaxed eutectic Si particles, the refined units and the prevented precipitations.

In our previous works, the effects of forging and heat treatment variables on microstructure evolution and mechanical properties have been studied for an ingot-metallurgy Re-bearing nickel base superalloy. To overcome the issues associated with the production of large-scale ingots and fine-grained workpieces, in the present work, the effect of hot forging and heat treatment variables was studied in a Re-bearing nickel base superalloy prepared via powder metallurgy. The purpose of the study was to reach the properly balanced mechanical properties for the potential use of the superalloy as a disc material. The initial as-HIPed workpieces were subjected to different hot forging and post-forging heat treatment or only to heat treatment (no forging). For the processed workpieces, the recrystallization behavior, size, morphology and volume fraction of γ′ precipitates were evaluated by scanning electron microscopy followed by a study of mechanical properties. The most properly balanced mechanical properties (strength, ductility, creep resistance and creep rupture lifetime) were reached for the γ grain size of dγ ≈ 13.6 µm. A finer and coarser γ grain size (down to dγ ≈ 2.6 and up to dγ ≈ 37.5 µm) even when superimposed with a higher volume fraction of dispersed secondary γ′ precipitates (in the case of dγ = 27–37.5 µm) was associated with worse mechanical properties.

This paper encompasses the development of a microstructure-based numerical model (FEM) of the conveyor cooling process after the hot forging of industrial steel with accurate predictions of the volume fraction of phases as yield and tensile strengths. An experimental procedure for validating the FEM was conducted using optical and scanning electron microscopy and tensile tests. Results showed very good agreement between the phase predictions of the 3D FEM model and those obtained from direct measurement of forged parts, with an average error of about 3.6 and 6.9% for ferrite and pearlite phases, respectively. Tensile test results were evaluated at a 90% reliability level, and very good agreements were obtained with an error of about 3 and 5% for the yield and tensile strengths. The methodology could predict the phase transformations, and the mechanical properties during cooling after the hot forging of the steel were investigated. [ABSTRACT FROM AUTHOR]

The control forging and cooling experiments of H13 and Cr8 die steel were carried out on a MMS-200 thermal simulator. When the cumulative strain of H13 steel reached 2.302 by drawing once, the number of recrystallized grains increased, the recrystallized grains were refined and the corresponding grain grade was about eight. The grain was refined with deformation bands at 750 °C in non-recrystallization region. With increasing cooling rate, the distorted austenite grains evolved into fine recrystallized grains and distorted austenite grains. The microhardness value of annealed H13 steel increased and then decreased with increasing cumulative strain and cooling rate, decreased and then increased with increasing drawing temperature. When the cumulative strain was 1.609 by drawing twice for Cr8 steel, the distribution and quantity of carbide particles were improved. With increasing deformation temperature, the size and number of carbide particles decreased and the dissolution degree increased significantly. Moreover, the intragranular carbide particles dissolved preferentially into matrix. With increasing cooling rate, it presented acicular martensite with granular carbides. The microhardness value of Cr8 decreased first and then increased with increasing cumulative strain and cooling rate, and increased and then decreased with increasing drawing temperature. [ABSTRACT FROM AUTHOR]

Forging and low-temperature solid solution treatment to regulate Mg-12.8Gd-3.8Y-1.9Zn-0.5Zr (wt%) alloy were investigated in this paper, which exhibited a heterogeneous microstructure. The alloy demonstrated a yield strength (YS) of 266.68 MPa, an ultimate tensile strength (UTS) of 337.01 MPa, and elongation (EL) of 8.98 %. It was shown that the strength and ductility of the Mg-12.8Gd-3.8Y-1.9Zn-0.5Zr (wt%) alloy were synergistically enhanced. This enhancement can be attributed to the alteration of the second phase particles through low-temperature solid solution treatment, as well as the hardening effect induced by hetero-deformation. The low-temperature solid solution treatment allowed the large-sized brittle Mg 5 RE phase to be dissolved, while the deformation-induced dislocation tangle in the coarse grains (CGs) promotes the co-segregation of Gd and Zn elements, resulting in the precipitation-strengthened γ ′ phase. The presence of dynamically precipitated phases within the dynamic recrystallized (DRXed) zone enhanced the strain regulation ability in different regions and inhibited crack propagation. Furthermore, the hetero-deformation induced (HDI) hardening effect, arising from the interaction between CGs and fine grains (FGs) in the heterogeneous microstructure, effectively prevented necking and improved ductility. [Display omitted] • A new method for regulating heterogeneous microstructures. • Regulation of γ' phase and refinement of Mg 5 RE phase improved mechanical properties. • HDI hardening effect effectively prevents necking and improvs ductility. [ABSTRACT FROM AUTHOR]

In this paper, finite element modeling of the forging process in step-wedge strikers of two different configurations was carried out. During the analysis of the results of the shape change and the parameters of the stress-strain state, it was found that the configuration with a wedge and a depression in the cross section is the best option. The microstructure evolution of the metal was simulated during its deformation in step-wedge-shaped strikers of the optimal configuration. For comparative analysis, models with variable values of geometric and technological parameters were studied. It was found that the angle of the junction of the wedge and the depression, as well as the heating temperature of the workpiece, have a significant effect on the intensity of grinding of the initial grain size. The change in the strain rate has a negligible effect on the change in the microstructure. Varying the values of the friction coefficient at the contact of the workpiece and the tool does not affect the intensity of grinding of the initial grain size. [ABSTRACT FROM AUTHOR]

Herein, Al-Si-Cu aluminum alloy was prepared and the effect of forging on the microstructure and mechanical properties of novel Al-9Si-5Cu-0.2Zr-0.1Sr-0.16Ti-0.1Ce cast aluminum alloy was investigated. The microstructure analyses show that after forging, the casting defects disappeared, and the irregular Si-eutectic was spheroidized and randomly distributed. The coarse intermetallic compounds (IMCs) gradually dissolved during the solution treatment, and the increased supersaturation of the matrix promoted precipitation kinetics, leading to the coexistence of dense fine θ and θ' strengthening phases. Moreover, the dislocation strengthening effect for the forged alloy was enhanced. The mechanical tests show that compared to the as-cast alloy, the mechanical properties of the forged alloy including the hardness, yield strength, tensile strength, and plasticity were improved by optimizing the microstructure. [ABSTRACT FROM AUTHOR]

Al/Mg/Al sheet with good bonding quality and mechanical properties was fabricated based on the proposed porthole die co-extrusion and forging (PCE-F) process. There were no voids, cracks or other defects on the Al/Mg interface. A continuous diffusion zone with two-sub-layer structure was formed across the Al/Mg interface, and its width increased with higher temperature or reduction ratio. The sub-layers formed at low and high temperature were identified to be solid solutions and intermetallic compounds (IMCs) including γ-Mg17Al12 and β-Al3Mg. In Al layer, the welding zone mainly consisted of fine equiaxed grains with several coarse elongated grains, while the majority of matrix zone is coarse elongated grains. The rolling textures were dominated in both welding and matrix zones. In Mg layer, the welding zone exhibited complete DRXed grain structure, while several unDRXed coarse grains were observed in the matrix zone. With the increasing temperature, the grain size of Al and Mg layer firstly decreased and then increased. High reduction ratio strongly refined the grain structure of Al layer, while slightly affected the Mg layer. The Al/Mg/Al sheet experienced stress-drops twice during the tensile test. The first stress-drop was determined by the IMCs and microstructure of Mg layer, while the second stress-drop was closely related to the microstructure of Al layer. Al/Mg/Al sheet forged at the lowest temperature without the formation IMCs exhibited the highest stress for the first stress-drop, and that forged under the highest reduction ratio with the smallest grain size in Al layer had the highest stress for the second stress-drop.

Strengthening of metals as a function of metal working and thermal treatment is being utilized effectively in steel structures. Effect on strength beyond thermomechanical treatment has been the focus of this research by imprinting a nature inspired pattern on one side of the sheet metal. Pangolin scale pattern overlapped on AISI 1040 sheet metal while preserving its base treatment. Microstructure, impact toughness, hardness, and tensile strength with notch opposite to worked side was investigated after forging and post forging heat-treatment. After heating at 800°C, overlapping patterned forging was done on one side of two plates and then subsequently cooled in two ways, air cooled, and water quenched. To analyze the effect of forging and heat treatment, Charpy impact, UTS, hardness tests, and metallography were carried out on the heat treated (forged + quenched), untreated (forged + air cooled) and base (as received) specimens. The Room temperature Charpy test showed that the untreated specimen has the highest impact toughness of 120 J as that of the base and heat-treated specimen, 44 J and 60 J respectively. The heat-treated specimen showed an increase in macro and micro hardness than for the base and untreated specimens. Whereas the UTS has dropped in untreated and heat-treated specimens as compared to the base specimen, because in tensile test load is applied uniformly throughout the specimen so the stress concentrations in the unforged side of the metal higher than the side which is forged with overlapping patterns.

Rotary forging was conducted for TA2 titanium samples with initial forming temperatures ranging from room temperature to 923 K. The microstructure of the samples was examined by using electron back-scattered diffraction and X-ray diffraction. The results indicate that rotary forging remarkably enhanced the formability of TA2 titanium and took a notable grain refinement effect over the whole temperature range. The theoretical calculation results indicate that enough working heat was generated during the early deformation stage to raise the temperature of the sample to above the dynamic recrystallization temperature. The deformation of titanium during rotary forging can be roughly divided into two stages as dislocation slip stage and the dynamic recrystallization stage. [ABSTRACT FROM AUTHOR]

In order to improve the performance of Ti-46Al-8Nb-0. 5Y-0. 2B alloy for internal combustion engine, the alloy was firstly subjected to the isostatic pressure and uniform annealing, and then treated via the 1 300 [isothermal twostep forging. The total deformation was controlled to be 75%,and then it was treated by air cooling (AC)and furnace cooing (FC), respectively. The microstructure and tensile properties were analyzed by means of experimental test. The results showed that the upper surface of many structures is formed after art cooing, and the lamellar thickness is about 43m. The center is long strip lamellar crystal structure. Many lamellar structures are formed on the sides. After the furnace cooled, the upper surface formed lamellar morphology, with the size approaching 60 "mother size of the central area decreases and more phase is formed. A layer of ^regular shapes formed on the sides. The tensile strength of the alloy structure obtains by art cooling is slightly higher than that obtained V1/ furnace cooling. When the tensile test is conducted at 800 [,the tensile strength of the alloy structure obtained V1/ art cooling method is 591 MPa, the yield strength was 472 MPa,and the elongation is 32%. The tensile properties of the alloy are brittle fracture along the crystal at room temperature. After being stretched at 800 no large dimples are formed in the fracture area, which mainly shows plastic deformation. After being stretched at 900 [a large number of dimples are formed in the fracture area, and the ductile fracture occurred mainly. [ABSTRACT FROM AUTHOR]

The effects of different morphologies of initial grains obtained by pre‐extrusion under different extrusion hole diameters or different extrusion temperatures on the microstructure and mechanical properties of forged Mg−Al−Zn−Ce alloy are studied. After homogenization treatment of as‐cast Mg−Al−Zn−Ce alloy, β‐Mg17Al12 phase is completely dissolved into the α‐Mg matrix. Then, pre‐extrusion deformation is conducted. Dynamic recrystallization (DRX) occurs during the pre‐extrusion process, and the initial grains with different grain sizes, second‐phase volume fractions, and textures are obtained. The pre‐extruded alloys show a strong basal plane (0001) texture and a monotonous increasing (or decreasing) change. After forging the pre‐extruded alloys, compared with the homogeneous forged alloy, the average grain size of the pre‐extruded‐forged (PEF) alloys is smaller and the texture strength is greatly weakened. As the microstructure of the pre‐extruded alloys, the PEF alloys show a monotonous increase (or decrease) in grain size, the volume fraction of the second phase, and texture strength. It is inferred that the microstructure and texture of PEF alloys evolve based on the microstructure and texture of the pre‐extruded alloys, and their mechanical properties are determined by the evolved microstructure and texture. [ABSTRACT FROM AUTHOR]

The paper presents the analysis of hot deformation behavior of Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) alloy using the theory of dynamic material modeling (DMM) based on hot compression tests performed to a total true strain of 1 at the strain rates from 0.01 to 100 s−1 and at the temperatures within the range between 800 and 1100 °C. The processing maps according to the Prasad's criterion were developed. The analysis of the processing maps allowed for the placement of domains describing the areas of potentially favorable combinations of hot deformation parameters. The microstructure observations of the investigated alloy specimens after hot deformation in stability and instability areas were conducted. The optimal processing parameters for numerical modeling of Ti-6246 alloy forging were selected based on processing maps. After complex analysis of the obtained results, microstructural observations and numerical modeling of forging of selected part, the forging tests of Ti-6246 alloy were realized. The obtained product quality assessment was carried out by computed tomography non-destructive testing. [ABSTRACT FROM AUTHOR]

We report on a methodology of powder sintering and in-situ press forging, which can be used to manipulate a new bimorphic microstructure in Ti-6Al-4V alloy. The microstructure contains typical triangle colonies with ultrafine lamellar α and β, and their border areas with ultrafine equiaxed α, dispersed nano/ultrafine β, as well as α/β interface L layers. Surprisingly, the bimorphic alloy exhibits excellent mechanical properties under both tensile and compressive conditions, far superior to other Ti-6Al-4V alloys and their composites reported so far. Therefore, this innovative methodology provides a simple and economical method for preparing high-performance metallic alloys in structural applications. We report on an innovative methodology of spark plasma sintering and in-situ press forging, which can be used to manipulate a new bimorphic microstructure in Ti-6Al-4V alloy. Surprisingly, the manipulated bimorphic alloy exhibits excellent mechanical properties under both tensile and compressive conditions, far superior to other Ti-6Al-4V alloys and their composites reported so far. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The study concerns cost-effective realization of Thermomechanical controlled processing (TMCP) in a forging process. The goal of the study was to produce mechanical properties of the steel in as-forged direct-cooled condition equivalent to those of quenched-tempered structural steel with simultaneous energy-savings benefits. The results of satisfactory implementation into hammer forging of a complex-geometry made of micro alloyed medium-carbon steel 38MnVS6 in industrial conditions are presented. The use of finite element analysis for estimation of proper run of cooling curves and full-scale simulation for reproducible hot deformation and cooling conditions resulted in producing Rm over 1 120 MPa with elongation reaching 20 %. [ABSTRACT FROM AUTHOR]

The concurrent use of micro-alloying additions and thermomechanical treatment is a common practice for obtaining high-quality grades of forged steels. Judicious use of chemistry, heat treatment schedule, and controlled processing can lead to a wide range of microstructure and thus final properties suitable for the production of different parts for the automobile industry. In this paper, thermomechanical treatment of Ni-added micro-alloyed steel containing Nb, V, Ti has been carried out with different deformation schedules (50-70%) at high temperatures followed by the varying cooling rate (i.e., forced air cooling, oil quenching, and water quenching). The cooling rates for three conditions were measured as 5 °C/s for forced air cooling, 40 °C/s for oil quenched, and 110 °C/s for water quenched samples. Thermomechanical and post-tempering treatment cycles were employed for the steel with 1150 and 900 °C as upper and lower forging temperatures. The best combination of properties viz; YS: 1044 MPa, UTS: 1308 MPa, % El: 16.7, %RA: 57 and Impact Toughness: 50 J/cm2 could be achieved for 70% deformed samples, followed by forced air cooling. The reasons have been attributed to the segregation of Ti & Nb carbides at grain boundaries as revealed by microstructural analysis. This has led to restriction of grain boundary coarsening at high temperatures. Further, fine vanadium carbide and the presence of retained austenite have contributed to improving the elongation and toughness values. [ABSTRACT FROM AUTHOR]

The aim of this work is to compare the technological and material properties of CMnCr steels without bismuth, with 0.08 wt. % Bi and 0.12 wt. % Bi. Experimental heats showed that the most advantageous alloying of Bi into the heat was in the ladle, with an efficiency of about 20%. The optimal temperature range for forming steel was found to be 1160–1050 °C. With increasing Bi content, the formability of steels and plastic properties decreased, while the yield stress and tensile strength increased. Manganese sulfides, aluminum oxides, or oxysulfides, which were segregated both individually and in clusters, were found in the matrix of all tested steels. In steels with Bi, the Bi particles segregate the separately in the form of globules, either as envelopes of elongated MnS or Al2O3 particles segregated in rows. Sulfur dot-shaped segregations in the steel with 0.12 wt. % of Bi and the steel without Bi were essentially uniform over the whole area. For the steel with 0.08 wt. % of Bi, both dot-like and ray-ordered sulfur segregations were observed. The microstructure of all tested steels was ferritic–pearlitic with islands of bainite. Towards the center of the forged bars, variable shape and size of bainite blocks were observed. Machinability tests evaluated by the extend of tool wear showed that the most advantageous was CMnCr steel alloyed with 0.08 wt. % Bi.

Three air-hardening forging steels are presented, concerning their microstructure and their mechanical properties. The materials have been produced industrially and achieve either bainitic or martensitic microstructures by air-cooling directly from the forging heat. The bainitic steels are rather conservative steel concepts with an overall alloy concentration of approximately 3 wt.%, while the martensitic concept is alloyed with 4 wt.% manganese (and additional elements), and therefore belongs to the recently developed steel class of medium manganese steels. The presented materials achieve high strengths (YS: 720 MPa to 850 MPa, UTS: 1055 MPa to 1350 MPa), good elongations (Au: 4.0% to 5.9%, At: 12.3% to 14.9%), and impact toughnesses (up to 37 J) in the air-hardened condition. It is shown that air-hardened steels achieve properties close to standard Q + T steels, while being produced with a significantly reduced heat treatment.

Effects of two-step aging treatment on the microstructure and mechanical properties of 7A99 forged aluminum alloy were studied using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile test and fracture toughness test. The results show that after 120℃/4 h+165℃/8 h two-step aging treatment, the ultimate tensile strength, yield strength, elongation and electrical conductivity are 548 MPa, 513 MPa, 12.0% and 38.2% IACS, respectively. Meanwhile, the L-T toughness fracture is 30.5 MPa·m1/2.The fracture mode of the alloy is transgranular dimple fracture mechanism, and the major precipitates are η' and η phases under the aging condition.

The processes of forging without canning were optimized, such that forging could be successfully performed and forged pancakes without cracks could be obtained. The maximum height reduction could reach 80%. The as-forged microstructure consisted of γ and β/B2 phases. The volume fraction of the β/B2 phase rose slightly compared to the pre-forging state. Near the top or bottom of the pancake, residual lamellae were found, while full dynamic recrystallization was completed at the center and lateral parts. Equiaxed γ grains illustrated that dynamic recrystallization mainly occurred in the γ phase, while the softer β phase coordinated the deformation by adjusting morphology. Two types of Σ3 boundaries, [110] 70° and [111] 60°, were found in the γ phase. At room temperature, the fracture was brittle, and the elongation was 0.07%. With increasing temperature, the yield strength and ultimate strength decreased, while the elongation increased. The brittle–ductile transition temperature was between 800°C and 850°C. [ABSTRACT FROM AUTHOR]

Al/Mg/Al sheet with good bonding quality and mechanical properties was fabricated based on the proposed porthole die co-extrusion and forging (PCE-F) process. There were no voids, cracks or other defects on the Al/Mg interface. A continuous diffusion zone with two-sub-layer structure was formed across the Al/Mg interface, and its width increased with higher temperature or reduction ratio. The sub-layers formed at low and high temperature were identified to be solid solutions and intermetallic compounds (IMCs) including γ-Mg 17 Al 12 and β-Al 3 Mg. In Al layer, the welding zone mainly consisted of fine equiaxed grains with several coarse elongated grains, while the majority of matrix zone is coarse elongated grains. The rolling textures were dominated in both welding and matrix zones. In Mg layer, the welding zone exhibited complete DRXed grain structure, while several unDRXed coarse grains were observed in the matrix zone. With the increasing temperature, the grain size of Al and Mg layer firstly decreased and then increased. High reduction ratio strongly refined the grain structure of Al layer, while slightly affected the Mg layer. The Al/Mg/Al sheet experienced stress-drops twice during the tensile test. The first stress-drop was determined by the IMCs and microstructure of Mg layer, while the second stress-drop was closely related to the microstructure of Al layer. Al/Mg/Al sheet forged at the lowest temperature without the formation IMCs exhibited the highest stress for the first stress-drop, and that forged under the highest reduction ratio with the smallest grain size in Al layer had the highest stress for the second stress-drop. [ABSTRACT FROM AUTHOR]