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The cellular automata (CA) method has played an important role in the research and development of metallic materials. CA can interpret the microstructure changes of materials and obtain more abundant, accurate and intuitive information of microstructure evolution than conventional methods. CA can visually represent the process of grain formation, growth, development and change to us in a graphical way, which can assist us in analysis, thinking and solving problems. In the last five years, the application of CA in materials research has been rapidly developed, and CA has begun to occupy an increasingly important position in the simulation research of metallic materials. After introducing the advantages and limitations of CA compared to other widely used simulation methods, the purpose of this paper is to review the recent application progress on the microstructure simulation of metallic materials using CA, such as solidification, recrystallization, phase transformation and carbide precipitation occurring during forming and heat treatment. Specifically, recent research advances on microstructure simulation by CA in the fields of additive manufacturing, welding, asymmetrical rolling, corrosion prevention, etc., are also elaborated in this paper. Furthermore, this paper points out the future work direction of CA simulation in the research of metallic materials, especially in the simulation of the crystal structure, the prediction of mechanical properties, CA simulation software and rule systems, etc. These are expected to attract wide attention of researchers in the field of metallic materials and promote the development of CA in materials research. [ABSTRACT FROM AUTHOR]

The present paper investigates the effect of carbon nanofibers (CNFs) on the microstructure and mechanical properties of Carbon fiber reinforced carbon and silicon carbide binary matrix (C/C–SiC) composite prepared by using the reactive melt infiltration technique. The CNFs used in this paper were generated through in-situ reaction in the pores of C/C preforms using the chemical vapor deposition. Results indicate introducing additional carbon sources in the form of CNFs in the C/C preform can remarkably improve the permeability of molten Si, resulting in higher density and more uniform microstructure of the RMI-deriver C/C–SiC composites. Consequently, the in-situ formation of CNFs reduces the residual Si content by 64.71% and increases the mechanical strength and modulus at room temperature by [22.31% and 17.89%] and after heat treatment at 1500 °C by [35.6% and 47.48%] with respect to no-CNF containing composites due to a lower amount of residual Si content and additional reinforcement effect of the unreacted CNFs. [ABSTRACT FROM AUTHOR]

The paper concerns the influence of heat treatment (annealing, quenching and aging) on the microstructure and hardness of flat bars samples from the CuAl10Ni5Fe4 alloy. The microstructures were observed in light and scanning electron microscopes. The appearance and area fractions of the martensite beta phase and their influence on the mechanical properties were examined. The annealing study at a temperature of 950 °C for 1 hour, followed by rapid quenching in water and subsequent tempering at a temperature of 350-500 °C for 15-120 minutes, demonstrated the potential for a significant increase in the hardness of aluminum bronze from approximately 200 HV3 up to 600 HV3. This suggests new possibilities for the material's applications. [ABSTRACT FROM AUTHOR]

This paper utilizes the plasma arc as the heat source to successfully fabricate well-formed thin-walled parts using combined cable wire duplex stainless steel 2209. Microstructure of parts exhibited the favorable two-phase ratio and the absence of σ-phase. It was found that appropriate heat input (1.68 kJ/cm) and cooling rate (5 °C/s) can effectively avoid the precipitation of σ-phase. Furthermore, the properties of the as-deposited samples were comparable to those of the samples heat-treated at 1300 °C, proving that no subsequent heat treatment was required for 2209 stainless steel fabricated by plasma arc additive manufacture. The samples showed excellent properties, in which the ultimate tensile strength and yield strength were improved by about 7% and 24% compared with GB/T4237-2015. The impact toughness meets the requirements of EN10028-7-2016, which is about 35% higher than that of the cold metal transfer samples, and the corrosion resistance is comparable to that of hot rolled 2205. [ABSTRACT FROM AUTHOR]

:In paper, recycled Al-1.15Mg-1.02Si-0.7Cu alloy was optical prepared by meiting and casting, the microstructural evolution of the alloy were analyzed by using optical nicroscopy(OM), scanning e!ectron microscopy (SEM), e!ectron back scattered diffraciion(EBSD) and transmission e!ectron nicroscope(TEM),the effects of heal treatment on the mechanical and corrosionlresistant properties of the extruded proUes were invesiigated. The results show that the recrystaliization of the alloy was competed by soiid solution at 550C and fine equaaxaal crystass were obtanned. The iime required for the alloys to reach peak hardness under artificia1 aging cond!tions at 155,175 and 195 C was 18,8 and 4 h, respectively, and the peak hardnesses were 132.96 HV,132. 94 HV and 132.22 HV, respectively, wtth the extruded profiles obtanning the highest tensle strength of 410. 42 MPa and higher elongation of 14. 75% under aging cond!tions at 175 C/8 h. The optimizedsoid solution process ss 550 C/1 hand the artifidal aging process ss 175 C/8 h. The tendency of the alloy to intergranular corrosion ss more pronounced,and the alloy corrodes most severely under peakaged cond!tions, followed by over-aged and weakest underaged. [ABSTRACT FROM AUTHOR]

The mechanisms of microstructure transformation and mechanical anisotropy of laser-MIG hybrid additive manufacturing TC11 titanium alloy after solution aging treatment are investigated. In this paper, different solution temperatures and cooling modes are applied to tailor the microstructure and improve high-temperature properties and anisotropy. The result shows the microstructure of the samples in the as-deposited state is dominated by a widmanstatten structure composed of lamellar α clusters. Following solution aging treatment, a large area of basket-weave structure is obtained in the samples. A major influence of spheroidization of lamellar α clusters and dynamic recrystallization on mechanical anisotropy is revealed. The heat-treated samples exhibit more superior combined strength, elongation, impact toughness. The hardness difference between the layers and mechanical anisotropy decreases. During high-temperature tensile tests, the tensile strength increases with rising solution temperature; while, the elongation shows the opposite trend. The tensile fracture exhibits abundant uniform equiaxed dimples, and the fracture mode changes from intergranular fracture to transgranular fracture. Solution treatment at 990 °C for 2 h followed by air cooling is considered to be the optimal heat treatment process. Consequently, it results in a high tensile strength of 811 MPa and an excellent impact toughness of 50 J, representing improvements of 16.08% and 71.08%. [ABSTRACT FROM AUTHOR]

The microstructures and mechanical properties of equiatomic CoCrFeMnNi high-entropy alloys (HEAs) treated with various processing parameters of laser surface heat treatment are studied in this paper. The typical inverse gradient-grained structure, which is composed of a hard central layer and a soft surface layer, can be obtained by laser surface heat treatment. A much narrower gradient layer leads to the highest yield strength by sacrificing ductility when the surface temperature of the laser-irradiated region remains at ~850 °C, whereas the fully recrystallized microstructure, which exists from the top surface layer to the ~1.05 mm depth layer, increases the ductility but decreases the yield strength as the maximum heating temperature rises to ~1050 °C. Significantly, the superior strength–ductility combination can be acquired by controlling the surface temperature of a laser-irradiated surface at ~1000 °C with a scanning speed of ~4 mm/s due to the effect of hetero-deformation-induced strengthening and hardening, as well as the enhanced interaction between dislocation and nanotwins by the hierarchical nanotwins. Therefore, retaining the partial recrystallized microstructure with a relatively high microhardness in the central layer, promoting the generation of hierarchical nanotwins, and increasing the volume proportion of gradient layer can effectively facilitate the inverse gradient-grained CoCrFeMnNi HEAs to exhibit a desirable strength–ductility synergy. [ABSTRACT FROM AUTHOR]

This research paper examines the effect of different solution heat treatments parameters (temperature and time) on Al–3.39%Cu–2.26%Mg (wt%) alloy's microstructure, thermal, mechanical and corrosion properties. 5754 alloy and Al–Cu alloy are used to make Al–3.39%Cu–2.26%Mg (wt%) by gravity die casting. Solution heat treatment at different temperature and time (500 °C-10 min, 500 °C-4h, 530 °C-10 min and 530 °C-2h). As-cast Al–Cu–Mg alloy have α-phase and eutectic phase. After solution heat treatment and aging, precipitates phases is observed in microstructure. X-ray diffraction analysis results have shown that a precipitate phase [S phase (Al2CuMg)] gets formed in as-cast conditions but undergoes dissolution during the solution heat treatment process. As-cast Al–Cu–Mg alloy has a Brinell hardness value of 77.2 HB. As-cast alloy has S (Al2CuMg) precipitate phase increases hardness by precipitation strengthening. After solution heat treatment and aging, Brinell hardness reduces. After solution heat treatment (500 °C for 4 h) and aging (200 °C for 5 h), Brinell hardness values becomes 63.6 HB (− 17.6% decrease). Corrosion resistance improves after the solution heat treatment due to the dissolution of the precipitate phase, forming an almost single-phase solid solution. The as-cast alloy exhibits a peak compressive stress of 494.2 MPa, which increases after solution heat treatment and water quenching to 572.7 MPa (without aging). After aging, peak compressive stress decreases to 508.4 MPa. Failure strain for the as-cast alloy is 39.6%, reducing to 31.1% after solution heat treatment and water quenching. It again increases to 43.1% after aging. [ABSTRACT FROM AUTHOR]

Microstructural characteristics and mechanical properties of the ductile iron in three heat treatment processes (normalizing, quenching + high‐temperature tempering and isothermal quenching) were investigated in this paper. The pearlite and ferrite with large‐sized spherical graphites can be obtained in the normalized sample, and the spherical graphites with relatively large size can still be observed in the mechanical mixture of tempered martensite and acicular ferrite for the quenched‐tempered sample. Meanwhile, the lower bainite accompanied with the relatively fine spherical graphites are existed in the isothermal‐quenched sample. The difference of tensile strength is mainly caused by the phase composition, distribution and size of the spherical graphites and the effect of the solid solution strengthening. The weaker degree of the debonding damage, higher proportion of high‐angle grain boundaries will improve the impact toughness of the ductile iron. In a word, the optimum combination of strength and toughness is acquired by using isothermal quenching, and the tensile strength and impact toughness are ~1350 MPa and ~10.62 J, respectively. [ABSTRACT FROM AUTHOR]

This paper mainly investigated the effect of the Mn/Ag ratio on the microstructure and room temperature and high-temperature (350 °C) tensile mechanical properties of the as-cast and heat-treated Al-6Cu-xMn-yAg (x + y = 0.8, wt.%) alloys. The as-cast alloy has α-Al, Al2Cu, and a small amount of Al7Cu2 (Fe, Mn) and Al20Cu2 (Mn, Fe)3 phases. After T6 heat treatment, a massive dispersive and fine θ′-Al2Cu phase (100~400 nm) is precipitated from the matrix. The Mn/Ag ratio influences the quantity and size of the precipitates; when the Mn/Ag ratio is 1:1, the θ′-Al2Cu precipitation quantity reaches the highest and smallest. Compared with the as-cast alloy, the tensile strength of the heat-treated alloy at room temperature and high temperature is greatly improved. The strengthening effect of the alloy is mainly attributed to the nanoparticles precipitated from the matrix. The Mn/Ag ratio also affects the high-temperature tensile mechanical properties of the alloy. The high-temperature tensile strength of the alloy with a 1:1 Mn/Ag ratio is the highest, reaching 135.89 MPa, 42.95% higher than that of the as-cast alloy. The analysis shows that a synergistic effect between Mn and Ag elements can promote the precipitation and refinement of the θ′-Al2Cu phase, and there is an optimal ratio (1:1) that obtains the lowest interfacial energy for co-segregation of Mn and Ag at the θ′/Al interface that makes θ′-Al2Cu have the best resistance to coarsening. [ABSTRACT FROM AUTHOR]

This paper aims to compare two ceramic materials available for additive manufacturing (AM) processes—vat photopolymerization (VPP) and material extrusion (MEX)—that result in fully ceramic parts after proper heat treatment. The analysis points out the most significant differences between the structural and mechanical properties and the potential application of each AM technology. The research revealed different behaviors for the specimens obtained via the two mentioned technologies. In the case of MEX, the specimens exhibited similar microstructures before and after heat treatment. The sintering process did not affect the shape of the grains, only their size. For the VPP specimens, directly after the manufacturing process, irregular grain shapes were registered, but after the sintering process, the grains fused, forming a solid structure that made it impossible to outline individual grains and measure their size. The highest compression strength was 168 MPa for the MEX specimens and 81 MPa for the VPP specimens. While the VPP specimens had half the compression strength, the results for the VPP specimens were significantly more repeatable. [ABSTRACT FROM AUTHOR]

In this paper, the Al–K2ZrF6–KBF4 reaction system, a melt reaction method, was used to prepare in situ ZrB2/AA6111 particle-reinforced aluminum matrix composite. The modification of friction stir processing (FSP) and T6 heat treatment (HT) was carried out for this composite for the first time. The reinforcing particles in the stirring zone after FSP+HT were refined from 1.7–1.9 to 0.1–0.3 μm. The grain size was refined from 10–50 to 2–5 μm and then slightly coarsened to 3–10 μm. The tensile strength of the FSP stirring zone is 193.40 MPa, the elongation is 29.33%, and the average hardness is 60 HV. The hardness of the stirring zone is not uniform and fluctuates in a large range of 53–80 HV. After the T6 heat treatment, the tensile strength of the stirring zone increased by 63.8% to 316.75 MPa. The tensile strength was 13% higher than that of T6-6061. The elongation remained at 30.12% and did not decrease. The elongation is 10% higher than that of other 6xxx aluminum alloys and composites after T6 heat treatment. The plasticity-reduction of the conventional alloy after T6 heat treatment was solved. The property is more uniform and the average hardness is 120 HV. Calculated by the theoretical model, the yield strengths of the stirring zone of the original composite, FSP, and FSP+HT composites were more than 96% consistent with the experimental values. [ABSTRACT FROM AUTHOR]

The Bi 2 Sr 2 CaCu 2 O 8+ x (Bi-2212) material, a high-temperature superconductor, holds significant promise for future high-field applications because of its multifilamentary, twistable production capabilities, coupled with a high upper critical field. Bi-2212 round wire (RW) is made by the powder-in-tube (PIT) technique, and Bi-2212 coils are usually being developed using the wind-and-react method and a high temperature and over-pressure (OP) heat treatment (50 atm, 890℃) is then required to achieve the high current performance. However, over-pressure (OP) heat treatment can lead to a reduction in wire diameter, compromising the stability of the coil structure. Addressing this issue, the pre-overpressure (pre-OP) heat treatment is used and proves effective in mitigating the reduction in Bi-2212 wire diameter. In this paper, to comprehensively investigate the impact of pre-OP heat treatment on the microstructure of Bi-2212 wire, a metallographic analysis of two kinds of Bi-2212 wires was carried out by the scanning electron microscope (SEM) and the ImageJ software. It was found that larger-area filaments experienced a greater reduction in area after pre-OP heat treatment, that pre-OP heat treatment increases the aspect ratio of filaments, and polygonal bundle structure helps maintain filament structure stability during pre-OP heat treatment. Additionally, the impact of pre-OP heat treatment on the performance of Bi-2212 wires was analyzed through critical current testing under high fields. [ABSTRACT FROM AUTHOR]

This paper presents an improved method for achieving controllable preparation of the composition and size of the monotectic alloy core-shell structure microspheres. This advancement is expected to enhance the commercial application of monotectic alloy core-shell structure microspheres. By installing a heating device at the top of the drop tube in the pulsated orifice ejection method setup, we achieved in-situ heat treatment of falling droplets, resulting in the successful preparation of Al 45 (Sn 42 Bi 58) 55 core-shell structure microspheres. Furthermore, we investigated the formation mechanism of the Al@Sn-Bi core-shell structure. Nine sets of Al-Sn-Bi microspheres with varying in-situ heat treatment temperatures were prepared. Analysis via X-ray diffraction and transmission electron microscopy revealed that the microspheres consisted of Al-rich, Sn-rich, and Bi-rich phases, without any intermetallic compounds. Scanning electron microscopy results indicated that as the in-situ heat treatment temperature increased, the structure of the Al-Sn-Bi microspheres transitioned from irregular to regular core-shell configurations. This suggests that higher heat treatment temperatures prolong liquid phase separation time, leading to increased repetition of Marangoni motion within the droplet, Ostwald ripening of the minor phase droplets, and Soret effect of the matrix phase. However, at temperatures exceeding 700 °C, the solidification rate of alloy droplets decreased, causing the Al-rich phase core to deviate from the center and form a crescent structure due to Stokes motion. [Display omitted] • A method is provided for the controllable production of monotectic alloy microspheres which have a core-shell structure. • Core-shell structure Al@Sn-Bi microspheres were prepared by the pulsated orifice ejection plus in-situ heat treatment. • Performing the microstructure evolution process of the core-shell structure Al@Sn-Bi microsphere. • Using TEM to observe the interface between Al and Sn, which composed of amorphous and nanocrystalline. [ABSTRACT FROM AUTHOR]

WAAM-LDM hybrid additive manufacturing can achieve high efficiency and high precision preparation of Ti-6Al-4V alloy. However, the inhomogeneous microstructure of WAAM-LDMed Ti-6Al-4V samples results in overall poor tensile properties. Therefore, this paper attempts to ameliorate the inhomogeneous microstructure of the hybrid sample by STA, and simultaneously improve the strength and plasticity. The results showed that the WAAM zone and HAZ were composed of α colonies, the RZ and LDM zone were distributed with fine basketweave structure of the AD samples. With the introduction of STA, the microstructure of each zone of the hybrid sample changes and transformed into a 'dual-phase' structure with bi-modal α p and β t. With the increase of aging temperature, the volume fraction of β t increased and the volume fraction of α p phase decreased, accompanied by the formation of bulk α phase and the coarsening of α s phase. It is worth noting that the strength of WAAM zone was obviously improved by STA, and the fracture positions of the STA samples were randomly distributed in the WAAM and LDM zones. Additionally, with the aging temperature increased, the strength of WAAM-LDMed samples was weakened, and the ductility was improved because the coarsened bulk α played a role of coordinating deformation in the tensile process. The excellent strength and ductility (UTS = 976 MPa, YS = 876 MPa, EL = 13.57%) of WAAM-LDMed samples was achieved at aging temperature 750 °C, compared with the AD samples (UTS = 860 MPa, YS = 767 MPa, EL = 12.5%). Finally, by optimizing the STA (940 °C/1 h/WQ + 750 °C/4 h/AC), the amelioration of the microstructure and the improvement of the strength-ductility of the hybrid samples were achieved. • The microstructure of WAAM-LDM sample is homogenized into α p + β t by STA. • STA treatment makes the strength of WAAM zone comparable to that of LDM zone. • The WAAM-LDM sample prepared by STA obtain excellent strength and ductility. [ABSTRACT FROM AUTHOR]

This paper proposes a new stretch bending approach for aluminum alloy extrusion profiles based on a novel pre-hardening forming (PHF) process. Tensile tests were carried out to examine the flow behavior and mechanical responses of a 7A09 extrusion profile in PHF process. Microstructure evolution was investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and small angle X-ray scattering (SAXS). It is interesting to find that the yield stress at 200 °C was higher than that at 185 °C. The quantitative analysis revealed that the higher volume fraction of precipitates (200 °C) played a greater role than the refinement of precipitate sizes (185 °C) in precipitation strengthening mechanism, thereby causing an enhanced hardening effect. This phenomenon indicated that there was a preferred temperature zone for the precipitation behavior in PHF process, and it also explained the lower yield stress at 185 °C than that at 200 °C. Additionally, similar results were also observed in strength of the warm-deformed alloys. The optimal strength (σ / σ 0.2 =589/517 MPa) can be achieved at 200 °C without subsequent heat treatment, which exceeded the typical strength of 7A09-T6 extrusion. The primary strengthening mechanisms in PHF process were strain hardening and precipitation strengthening, and the warm forming procedure caused a hardening effect, rather than a softening impact as in traditional warm/hot forming procedures. [Display omitted] • The yield stress and warm-deformed strength initially increased and then dropped with the increasing forming temperature. • An optimal warm-deformed strength superior to typical 7A09-T6 was obtained at 200 °C without subsequent heat treatment. • The higher volume fraction played a greater role than refinement of precipitate sizes in precipitation strengthening. • The warm forming procedure caused a hardening effect, rather than a softening effect during traditional warm/hot forming. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel idea of controlling microstructure and mechanical properties based on the non-equilibrium microstructure of nickel-based superalloy fabricated by laser powder bed fusion (LPBF). The network microstructures were firstly built in LPBF nickel-based superalloys by direct aging (DA) heat treatment. Thermodynamic calculations were conducted to design the DA and homogenizing + DA (HDA) heat treatments for elucidating the control mechanism. The results showed that the non-equilibrium microstructures in as-built nickel-based superalloy contributed to the network microstructure formation and recrystallization during DA heat treatment. The grains were refined and the <001> texture was eliminated after DA heat treatment. The non-equilibrium microstructures were removed and the recrystallized grains tended to coarsen after HDA heat treatment due to high temperature homogenizing treatment. The in-situ nano γ′ phase uniformly distributed in the grains of HAD-treated microstructures, which was also found inside network microstructures of DA-treated microstructures. Due to the additional strengthening effect of refined grains and network microstructures, the strength of DA-treated sample was higher than those of as-built and HAD-treated samples, while the ductility was lower than that of as-built sample, and but was close to that of HAD-treated sample. This study will provide guidance for developing a suitable heat treatment process of LPBF nickel-based superalloys. [ABSTRACT FROM AUTHOR]

Nickel-based GH3536 alloy exhibits high strength but low ductility when produced by selective laser melting (SLM), which hinders its widespread application in aerospace. This paper employed a 'two-step' method of heat treatment to optimize the microstructure of the SLM GH3536 alloy and investigated the mechanical properties. Tensile tests were conducted on SLM GH3536 alloy before and after heat treatment at 750 °C, using an in-situ high-temperature tensile stage. The relationship between the microstructural evolution and deformation behavior of the alloys was investigated by combining the in-situ tensile experiments and crystal plasticity finite element method (CPFEM). The results suggested that the elongation can be increased by 80% without a significant reduction in tensile strength. The improved elongation is attributed to the complete recrystallization, formation of annealed twins and serrated grain boundaries after heat treatment. The study also investigated the deformation behavior and fracture mode of the alloy before and after heat treatment. Discussion was done on the influence of the microstructure, particularly the twin and serrated grain boundaries on the alloy's plastic deformation. This study enhanced the understanding of plastic deformation of SLM GH3536 alloy and provided a valuable reference for the design and post-treatment of superalloy. • A two-step heat treatment method is proposed to prepare GH3536 alloy with high ductility and acceptable strength. • High-temperature microplastic deformation and damage of GH3536 alloy were observed in-situ SEM technique and its influencing factors were analyzed. • The effects of twins and serrated grain boundaries on the properties were simulated using the CPFEM model. [ABSTRACT FROM AUTHOR]

Due to the low production cost and light weight, copper-clad aluminum conductors show great potential value in the field of power transmission, while the phase structure and organizational changes at the Cu–Al interface in high-temperature environments have a great impact on the electrical and mechanical properties. In this paper, Cu–Al diffusion couples are prepared to study the diffusion process, microstructure, and growth kinetics of intermetallic compounds (IMCs) in Cu–Al interface during heating from 600 °C to 800 °C, and the mechanical and electrical properties of Cu–Al diffusion couples are discussed. The results show that after heat treatment, IMC layers are formed at the Cu–Al interface and the Al-side is composed of CuAl and CuAl 2 , in which the CuAl phase transforms from long to thick dendrites with the increase of temperature, and finally grows into a "popcorn" form. The IMCs at the Cu–Al interface from the Cu side to the Al side are in the order of Cu 3 Al layer, Cu 9 Al 4 layer, Cu 3 Al 2 layer and CuAl layer, among which the Cu 3 Al 2 layer is the thickest (168.42 μm at 700 °C), while the Cu 3 Al layer is the thinnest (37.32 μm at 700 °C). The kinetic calculations show that the diffusion layer grows up rapidly, which is caused by the generation of liquid-phase during the heating process, leading to the acceleration of the diffusion of Cu and Al. The kinetic factor of the Cu 3 Al 2 layer is the largest (n = 0.69), causing the fastest growth rate of the Cu 3 Al 2 layer, while the Cu 3 Al layer shows the largest activation energy for diffusion and the smallest diffusion rate (Q = 9.48 kJ/mol, D 0 = 2.06 × 10−1 m2/s), therefore its growth rate is the slowest. Based on the thermodynamic calculations and the Cu–Al phase diagram, a growth mechanism of the Cu–Al interface is proposed, the formation sequence of IMCs at the Cu–Al interface is Cu 9 Al 4 , CuAl, Cu 3 Al 2 and Cu 3 Al. The formation of IMCs layer at the Cu–Al interface leads to a significant increase in the hardness of Cu–Al samples (the hardness of the Cu 3 Al 2 is 10 times higher than that of Cu) and an obvious decrease in electrical conductivity (the electrical resistivity of Cu–Al is 5 orders of magnitude higher than that of Cu), affecting its application in the electrical industry. • Cu 3 Al, Cu 9 Al 4 , Cu 3 Al 2 , and CuAl were formed in the Cu–Al interface at 600°C–800 °C. • Cu 3 Al 2 layer has the excellent kinetic factor (n = 0.69) and the growth rate. • The formation mechanism of IMCs in the Cu–Al interface at 600°C–800 °C is proposed. [ABSTRACT FROM AUTHOR]

To achieve superior damage tolerance and fatigue properties, it is desirable for the microstructure of Ti-6Al-4V ELI (Extra Low Interstitial) titanium alloy to consist of equiaxed grains with a homogeneous lamellar structure. However, traditional forging and single additive manufacturing techniques require extreme processes such as quasi β heat treatment and hot isostatic pressing. In this paper, a hybrid directed energy deposition method that integrates in-situ rolling with simple annealing is proposed to simultaneously achieve these microstructures. The results indicate that the initial microstructures produced by hybrid directed energy deposition consist of fine equiaxed prior-β grains, inconspicuous interpass bright bands, randomly oriented lamellar structure and numerous small substructures at the TEM scale. Due to the plastic deformation caused by in-situ rolling, the primary β grains underwent significant refinement with a reduction in grain diameter from over 2000 μm to 113.8 μm. Besides, the unique microstructures and thickness of α laths are influenced by coarsening and dissolution mechanisms that are controlled by diffusion during phase transformation. Furthermore, a uniform microstructure without bright bands and excellent comprehensive properties can be achieved through heating at 880 °C for 2 h and natural cooling. These findings validate that hybrid directed energy deposition coupled with simple annealing present a novel and cost-effective approach for the direct manufacturing of uniform titanium alloy forgings. • Microstructure evolution in DED with in-situ rolling and annealing was studied in detail. • Uniform microstructure realized with fine equiaxed grains. • Driving forces and mechanisms of α lamellae evolution were summarized. • Optimal comprehensive properties were analyzed. [ABSTRACT FROM AUTHOR]

In this paper, the influence of electrical pulse treatment (EPT) on the evolution of microstructure and texture and the resultant magnetic and mechanical properties of a cold rolled Nb-alloyed non-oriented silicon steel (NOSS) was investigated carefully. When the temperature rise caused by Joule heat is higher than the starting temperature of dissolution, more precipitates are dissolved in the EPT specimens than those subjected to the conventional heat treatment (CHT) at the same temperature, and higher current density resulted in Laves precipitates dissolved at lower temperature. The permeability of all the EPT and CHT specimens increase first and then decrease with the increasing temperature, and it reaches the maximum at the temperature for nearly the complete recrystallization. B 50 is higher for the EPT specimen than CHT before the completion of recrystallization due to enhanced recrystallization, but lower than CHT after the completion because the athermal effect of pulsed current promotes the growth of γ-fiber grains, disfavoring the permeability. Moreover, the EPT specimen has the lower iron loss and lower yield strength than the CHT one at the same annealing temperature, because the dissolution of precipitates, recrystallization and grain growth in cold rolled matrix are all enhanced due to the athermal effect of pulsed current. [Display omitted] • Higher current density leads to Laves precipitates in NOSS dissolved at lower temperature. • The maximum B 50 in EPT samples appeared at lower temperature than that of CHT ones. • Athermal effect of pulsed current resulted in the lower iron loss and lower yield strength. [ABSTRACT FROM AUTHOR]

This paper investigated the microstructure and mechanical properties of AISI 430 ferritic stainless steel (FSS) after annealing in either the single-phase or two-phase region, followed by different cooling manners: water cooling, air cooling and furnace cooling. After annealing at 840 °C in the single-phase region, the sample consisted primarily of ferrite, with M 23 C 6 and M 2 (C, N) precipitates aligned mainly along the rolling direction (RD). For the water-cooled and air-cooled samples annealed at 950 °C in the double-phase region, they formed a dual-phase structure comprising ferrite and martensite, with precipitations primarily located within the martensite lath. Conversely, the sample subjected to annealing at 950 °C followed by furnace cooling displayed a single ferrite structure, owing to the decomposition of austenite. In this case, the precipitations were mainly found along the grain boundaries, with some also forming within the ferrite grain. The paper delved into the analysis of mechanical properties and strengthening mechanism through tensile experiments and fracture morphology examination. The influence of heating range and cooling manner on the yield characteristics of FSS was discussed. The results indicated that the air-cooled and furnace-cooled samples annealed at 840 °C displayed a clear yield platform in their tensile curves. Conversely, the samples treated with other heat treatments exhibited continuous yielding or no obvious yield platform. This difference may be attributed to the influence of heating temperature range and cooling manner on the distribution of dislocations and interstitial atoms within the ferrite grains. [ABSTRACT FROM AUTHOR]

The uncontrollable directional grain growth and non-equilibrium microstructure of Inconel 718 will form during laser direct energy deposition (LDED), which seriously limits the promotion and application, so it is necessary to consider the heat treatment to improve the microstructure and mechanical properties. In this paper, the effects adopting different heat treatments on the phase composition, precipitation behavior, grain structure, tensile and tribological properties of LDED Inconel 718 have been systematically investigated, with as-deposited samples compared. The results show that the number and size of γ″ phases can be significantly changed under different aging and solution conditions, and the strength and wear resistance increase while elongation decreases since the fine grain and precipitation strengthening occurring during heat treatment. By comparing the different samples, the SA1100A exhibits the highest yield and tensile strength, with 140.6% of yield strength and 83.9% of ultimate tensile strength increasing compared to as-deposited samples, also showing the narrowest wear mark width and the lowest average mass loss. [ABSTRACT FROM AUTHOR]

For zirconia continuous fibers, tensile strength is a very important performance parameter, which is affected by the crystal phase, its stability, grain size, processing temperatures, and so on. In this paper, the crystalline phases were adjusted through the Y 2 O 3 contents and heat treatment temperatures in the range of 1000–1500°C. We found that interfacial segregation of Y3+ at high temperatures led to crystal phase instability, which was observed near the grain boundaries of the 13.8YSZ fibers. At high temperatures, the grain growth of different fibers occurred to different degrees. The regularities between the tensile strength, the strength retention and temperature, Y 2 O 3 contents were discussed in detail. According to the highest tensile strength of a single fiber and Weibull modulus m, we found that the 5.4YSZ fibers were the most stable with the highest tensile strength and slow grain growth rate. The average strength was 1.6 GPa after heat-treating at 1500°C and the strength retention rate was about 54% under 1500°C for 60 min. Finally, the twistable 5.4YSZ continuous fibers with high strength were obtained by dry spinning technology. These results can provide reliable theoretical support and data sources for its high-temperature applications. • The twistable 5.4YSZ continuous fibers had a tensile strength of 1.6 GPa after 1500 °C. • Strength retention rate of 5.4YSZ continuous fibers was up to 54 % after 1500 °C/60 min • Crystalline phase was stable and grain growth was controlled through Y 2 O 3 content. [ABSTRACT FROM AUTHOR]

• Heat treatments reduced the hydrogen induced cracking sensitivity (HIC) of pipeline steel, increasing the ductility of steel and decreasing the number and the size of surface HIC microcracks. • Compared with water cooling, air cooling promoted the formation of precipitated phase in steel, which promoted the formation of deep hydrogen trap. • Air cooling process reduced concentration of diffusible hydrogen and the degree of local distortion of steel. In this paper, the hydrogen induced cracking (HIC) sensitivity of the austenitized Cu-containing pipeline steels after cooling processes in air and water conditions was evaluated. Microstructural test, as well as hydrogen-charging slow strain rate tensile test and hydrogen concentration tests were conducted. Results indicated that steels after both cooling processes exhibited lower HIC sensitivity compared to the untreated steel. Elongation and percentage reduction of area after the hydrogen-charging slow strain rate tensile tests were increased. This was related to the formation of strong hydrogen trapping sites and the decrease of weak hydrogen trapping sites such as high-angle grain boundaries. Moreover, the TDS test results confirmed the presence of more stable hydrogen trapping sites in air-cooled steel than water-cooler steel. The latest phenomenon effectively hindered the diffusion behaviour of hydrogen in steel and reduced the HIC sensitivity. [ABSTRACT FROM AUTHOR]