Solution Heat Research Articles

EVALUATING THE TENSILE AND IMPACT STRENGTH OF SOLUTION HEAT TREATED AL6061/2%GR/0-6%AL₂O₃ COMPOSITES FOR PISTON APPLICATIONS

This research evaluates the tensile and impact strength of Solution Heat Treated (SHT) Al6061/2%Gr/0-6%Al₂O₃ composites for piston applications. The associated mechanical loads on the piston crown may have severe consequences of lowered tensile strength and toughness value, which had led to overheating, leakage of oil with smoking exhaust; high fuel consumption rate and reduction in speed may have resulted into engine failure. The aim of the study is to examine the effect of varying amounts of Al₂O₃ (0%, 2%, 4% and 6%) on the tensile and impact strength of Al6061/2%Gr composites processed through solution heat treatment (SHT) that will be used as piston material; to evaluate the effect of solution hating and ageing temperatures on the composites and compare with the control sample. The Alumina powder (99.5% purity) was employed to strengthen the Al6061/Gr dual matrix composites and also improve its mechanical properties. Solution heat treatment was conducted at varying temperatures (400°C, 500°C, 600°C) and durations (1, 1.5, 2 hours), followed by ageing at varying temperatures (150°C, 175°C, 200°C) and durations (2, 4, 6 hours). The factors and optimal levels were identified using Minitab Result. The Taguchi L9 Orthogonal Array in Minitab was run using the factors and levels. The mechanical properties were evaluated through tensile and impact testing. The results reveal significant improvements in tensile and impact strength with higher Al₂O₃ content, offering insights into their suitability for high-stress applications, such as pistons.

Microstructure evolution during solution annealing of an Al–Zn–Mg–Cu alloy with La additions

The high-strength 7xxx Al alloys are frequently used due to their excellent properties. To achieve these properties, heat treatment is crucial. In this study, the influence of La on the microstructure evolution of Al–Zn–Mg–Cu alloys during solution annealing, the first step of heat treatment, was investigated. The results showed that La additions significantly affect the microstructure by increasing in the eutectic solidus temperature, influencing the melting enthalpy of Mg2Si/LaAlSi, promoting the formation of LaAlSi and reducing Mg2Si, increasing the melting enthalpy of α-Al, shortening the time to reach the eutectic melting peak and preventing a significant increase in grain size. A 10 h solution heat treatment was recommended, with minimal benefits after 12 h. 0.15 wt% La was the minimum to prevent an increase in grain size. La altered the Al45Cr7 phase and formed a new Al20Cr2La phase with larger dimensions and sharper edges. Faster cooling rates refine the grain size due to precipitation along the grain boundaries. The content of the T-phase (Mg32(Al, Cu, Zn)49) decreased with increasing annealing time. Prolonged annealing promoted the diffusion of Mg and Zn from the eutectic phases, which led to their dissolution in the matrix. Zn diffused out first, followed by Mg. Prolonged annealing favored the formation of the Al7Cu2Fe phase over the Al13Fe4 phase.

The Effect of Pre-Treatment on the Rehydration of Dried Apple Cube

The subject of the research was a comparative analysis of the rehydration process of dried apples in cubic form. Cubes of dried Idared apples were subjected to various pre-treatment processes, including steam blanching, microwave heating and osmotic dehydration in a sucrose solution. The pre-treatment was followed by a convection drying process conducted using two different drying systems. The rehydration process was carried out at a water temperature of 20 °C for 150 min. Rehydration kinetics, instantaneous increments in rehydrate mass and the relative and absolute moisture content of rehydrated samples were analyzed based on the tests. The rehydration process rates were also determined. It was observed that osmotic drying in a 10% sucrose solution reduced the rehydration process of dried apples by up to 32%.

Exploring Efficient and Energy-Saving Microwave Chemical and Material Processes Using Amplitude-Modulated Waves: Pd-Catalyzed Reaction and Ag Nanoparticle Synthesis

This study investigated the impact of a 10 kHz amplitude-modulation (AM) wave from a semiconductor microwave generator on the heating of ultrapure water and electrolyte aqueous solutions containing NaCl. It also examined the effects of AM waves on the yields of 4-methylbiphenyl (4-MBP) in the heterogeneous Suzuki–Miyaura coupling reaction, which was conducted in the presence of palladium nanoparticles supported on activated carbon (Pd/AC), as well as their influence on the growth rate during silver nanoparticle synthesis. Applying AM waves, typically used in telecommunications, enhanced heating efficiencies and improved product yields in both the chemical reaction and nanoparticle growth. Irradiating with microwaves under AM conditions allowed it to reduce power output while still achieving target yields and growth rates, even at the same temperatures without AM. This indicates the potential for highly efficient and energy-saving microwave processes in chemical reactions and material synthesis.

Performance of Pico-Second Laser-Designed Silicon/Gold Composite Nanoparticles Affected by Precision of Focus Position

Pulsed laser ablation in liquids is one of the most versatile and widespread techniques for the easy synthesis of different types of nanoparticles with controllable properties. A huge amount of energy compressed into one pulse that is directed onto a solid target leads to the ejection of materials into surrounding liquid. However, the precision of the focus of laser irradiation can play a crucial role in the synthesis of nanomaterials and, hence, significantly affect their physico-chemical properties. In this paper, we investigated the influence of the focus position of the laser spot on the optical properties of single- and double-element composite silicon/gold nanoparticles, as well as on their structure and chemical composition. Deepening of the focus to 0.5 mm inside the bulk material led to better chemical stability of the colloidal solutions and increased the particle and mass concentrations of the generated nanoparticles. This larger amount of materials led to a stronger absorbance, and resulted in slightly better photoluminescence excitation efficiencies for all nanostructures. Silicon-based nanoparticles had a remarkable photoluminescence peak at ~430 nm upon xenon lamp excitation, which was the most pronounced for pure silicon nanoparticles synthesized at the F+0.5 focus position. This position also led to the best laser-induced heating (~0.85 °C/min) of the colloidal solutions. All nanocomposites revealed amorphous silicon structures with some Si(111) and Au(111), suggesting the formation of gold silicide with different stoichiometries. The observed findings can help in choosing appropriate experimental conditions to achieve the best performance of laser-synthesized colloidal solutions of composite silicon/gold nanostructures.

Development of Anti-Icing and Skid-Resistant Road Surfaces Using Methyl Methacrylate (MMA) Resin-Based Composites

Winter road safety is significantly compromised by ice formation, leading to increased vehicular accidents due to reduced friction. Traditional anti-icing strategies, such as chemical deicers, present environmental and structural drawbacks, necessitating innovative solutions. This study evaluates methyl methacrylate (MMA)-based resin composites for anti-icing and skid-resistant applications. These composites are particularly intended for application on asphalt and concrete pavements in urban roads, highways, and other high-traffic areas prone to icing during winter. MMA composites exhibit excellent mechanical properties, including tensile strength of up to 10 MPa and compressive strength of 34 MPa under optimized formulations. These composites are specifically developed for application on asphalt and concrete pavements commonly found in urban roads, highways, and other high-traffic areas, where icing and skid resistance are critical challenges during winter conditions. Anti-icing performance was enhanced by incorporating additives like magnesium chloride hexahydrate, achieving a freezing point reduction to −12.9 °C and a heat of solution of 0.429 kJ/g. Laboratory tests revealed that increasing anti-icing additives reduced ice adhesion and melting time, with a trade-off in compressive strength, which decreased from 30 MPa (unmodified) to 16 MPa at higher additive concentrations. Skid resistance was improved through the addition of high-friction aggregates, ensuring durability under icy and wet conditions. These results highlight MMA composites as a sustainable and cost-effective alternative to traditional deicing methods, offering enhanced road safety and reduced environmental impact. Further research is recommended to optimize formulations and validate performance through field trials under varying climatic conditions.

Effect of thermo-mechanical age hardening on the strength and electrical conductivity of Copper-AA6063 bimetallic wire.

This research explored the impact of age-hardening treatment on the mechanical response and electrical resistivity of copper-clad AA6063 alloy bimetallic wire, with a focus on microstructural analysis and interface characterization. In this study, AA6063 alloy wire was inserted into an oxygen-free high conductivity copper tube, and a bimetallic wire was fabricated through a wire drawing process that reduced the cross-sectional area in 13 stages. The bimetallic wire underwent a series of thermo-mechanical treatments, including various combinations of wire drawing, solution heat treatment, and artificial aging. The findings revealed that applying solution heat treatment prior to wire drawing, followed by artificial aging after drawing, produced a clean interface free of intermetallic compounds. This processing approach resulted in a Cu-Al bimetallic wire with a strength of 286MPa and an electrical conductivity of 80% IACS. Furthermore, the electrical conductivity-to-density ratio reached 13% IACS/(g·cm⁻³), representing a 16% improvement over oxygen-free high conductivity copper.

Investigating the anisotropic behavior and high-temperature mechanical properties of GH4251 nickel-based superalloy prepared by selective laser melting and post heat treatment

GH4251 nickel-based superalloy prepared by selective laser melting (SLM) exhibits pronounced anisotropy. In this study, the anisotropic behavior and high temperature mechanical properties of SLMed GH4251 superalloy with different solution heat treatment temperatures (1070°C, 1120°C, 1130°C and 1170°C) at 700°C were systematically investigated. The results reveal that there is a temperature inflection point among 1120°C-1130°C, below which GH4251 superalloy shows an obvious {001} texture orientation in the deposition direction, making the alloy exhibit a significantly higher elongation under a comparable tensile strength. Above the inflection point, a large number of secondary γ' phases are precipitated out and the dynamic recrystallization of the superalloy occurs, which significantly reduces the mechanical anisotropy. Additionally, the study delves into the detailed discussion of the strengthening mechanisms of the SLMed GH4251 superalloy.

Microstructure Characterisation and Modelling of Pre-Forging Solution Treatment of 7075 Aluminium Alloy Using Novel Heating Methods

This study evaluates the effectiveness of these conventional heating methods, commonly adopted in the industry with long durations (typically one hour), in comparison to newer, potentially more efficient approaches such as induction coil heating, infrared module heating, and infrared furnaces that can perform solution heat treatment in significantly shorter times (5 to 20 min). The properties of the edge and centre regions of the solution-treated billets, including the state of precipitates, grain structures, and Vickers hardness, are investigated and compared. Results have shown that the 7075 billets heated by conventional heating methods sufficiently dissolved the stable precipitates, achieving hardness ranging from 137 to 141 HV, in contrast to the benchmark unheated, as-received sample of approximately 70 HV. In the meantime, the induction coil and infrared furnace demonstrate notable effectiveness, achieving hardness between 126 and 135 HV. The average grain sizes in the centre and edge regions for all samples are measured as 3 and 8 µm, respectively. However, the impact of the grain size on the hardness is negligible compared to the impact of the precipitates. Finite element (FE) modelling comparing the slowest heating method—the electric furnace—and the fastest heating method—induction coil heating—reveals the latter could heat the billet up to 450 °C at a rate ten times faster than the electric furnace. This study highlights the potential of novel heating techniques in promoting the efficiency of heat treatment processes for 7075 aluminium alloys.

Investigating the Effect of Volumetric Energy Density on Tensile Characteristics of As‐Built and Heat‐Treated AlSi10Mg Alloy Fabricated by Laser Powder Bed Fusion

Pore emergence during the laser powder bed fusion (LPBF) technique significantly impairs mechanical characteristics. Therefore, the elimination of pores is a pressing issue to ensure the quality and productivity of manufactured components. The objective of this study is to evaluate how certain parameters, such as laser power, layer thickness, exposure time, hatch distance, and volumetric energy density, affect the microstructure and tensile properties of AlSi10Mg specimens generated by LPBF in both their original state and after undergoing a solution heat treatment. The volumetric energy density (VED) is often used to optimize process parameters in the LPBF approach since it thoroughly evaluates all four main factors. This article specifically examines the impact of VED on the microstructural features and tensile characteristics of printed parts. The high VED of 78.13 J mm−3 decreases the occurrence of porosity and defects, hence enhancing the tensile characteristics of the specimens produced. Regarding specimens that have undergone solution heat treatment, the recommendation is to decrease the laser power to 350 W, which results in a VED of 60.76 J mm−3 and outstanding tensile characteristics. These findings provide fresh perspectives to achieve improved tensile properties of AlSi10Mg parts using LPBF processing settings.

Investigating photon emissions from homeopathic potencies

Studies using solvatochromic dyes appear to show that potencies have a polarising and structuring effect in solution. Taking these results further it can be predicted that on dissolution of solution structures, both heat and light should be emitted. It has been shown that a weak electric current passed through solutions of Antimonium crudum destroys the potency, as judged by its effect on the solvatochromic dye ET33. To see if potencies emit light on application of an electric current concomitant with this destruction of activity, a specially adapted ultra-sensitive luminometer has been employed which allows currents of pre-determined voltage to be passed through both control solutions and potency solutions in situ. Preliminary results indicate that photons are emitted from potency solutions beyond those of control solutions. What is particularly interesting is that photon emission does not occur immediately on application of an electric current but a significant delay occurs before emissions are seen. In addition, emissions appear to show evidence of oscillations over time before finally dying out. Results will be discussed in relation to previous studies on the physical chemistry of potencies and what these results might be telling us about the fundamental nature of potencies.

Enhanced photocatalytic H2 generation via in-situ grown CuO-decorated TiO2 nanotubes on Ti-Cu alloys: A synergistic thermo-electrochemical approach

In the present study, we developed a thermo-electrochemical strategy to grow CuO self-decorated TiO2 nanotubes (TiNTs) on Ti-xCu alloys (x = 0, 2, 4, 6, and 8 wt%). The Ti-xCu metastable solid solution alloys were prepared by rapid quenching after solid solution heat treatment. Based on microstructural analyses, unlike all other samples, which consist of the α-Ti phase, the microstructure of the Ti-8Cu sample is biphasic, consisting of α-Ti and the Ti2Cu intermetallic compound. Electrochemical anodization of the Ti-xCu samples results in the in-situ formation of CuO nanoparticles decorating the TiO2 nanotubes on substrates containing Cu. As the Cu concentration increases, the order and integrity of the nanotube arrays gradually decrease while the Cu concentration within the nanotubes increases; however, the Ti-6Cu sample presents a satisfactory structural order and a uniform distribution of Cu. Based on XPS analysis, it has been determined that CuO is the main species decorating the TiNTs. This results in a maximum reduction of the band gap by approximately 0.5 eV for the Ti-6Cu sample compared to the pure Ti sample (3.35 eV), leading to improved absorption of visible light. Furthermore, the CuO species extended the lifetime of charge carriers, as demonstrated by electrochemical impedance spectroscopy. This combination of band gap reduction and enhanced charge carrier separation in Ti-6Cu resulted in a photocatalytic H2 production rate of 35.8 µL/cm2·h, more than ten times higher than the pure Ti sample. These findings hold significant promise for developing efficient and sustainable energy production systems.

Influence of the induced Na+/Cl- ionic polarization effects on multi-scale structures of maize starch during radio frequency heating.

Structural modification/unfolding of starch molecules can be improved by radio frequency (RF) treatment. This necessitates a better understanding of its action mechanism through rapid heating and dipolar/ionic molecular vibration effects. Native maize starch (NS) was subjected to RF heating in a NaCl solution to five target temperatures, and its effect on structural modifications was evaluated. Results showed that the conductivity, particle size distribution and zeta potential of RF heated starch increased with increasing temperature. RF energy had a significant effect on the vibration intensity of other skeleton modes. No new chemical bonds/groups were formed in the starch even though there was the effect of sodium/chloride ions with the added vibration intensity of the ions and the dipolar rotation movements resulted in changes in the disordered and/or ordered structures. The RF treatment at 70°C had the highest energy (10.4kJ) of inter-strand hydrogen bond, crystallinity (36.6%) and trough viscosity (2480 cp), but had the lowest crystallite dimension (13.7nm), full width at half maximum (14.4) of peak at 480cm-1, and breakdown (534 cp) and setback (784 cp) viscosities based on X-ray diffraction, Fourier transform infrared, and Raman and rapid viscos analyzer observations.

Customized Ultrathin Oxygen Vacancy-Rich Bi2W0.2Mo0.8O6 Nanosheets Enabling a Stepwise Charge Separation Relay and Exposure of Lewis Acid Sites toward Broad-Spectrum Photothermal Catalysis.

Designing robust photocatalysts with broad light absorption, effective charge separation, and sufficient reactive sites is critical for achieving efficient solar energy conversion. However, realizing these aims simultaneously through a single material modulation approach poses a challenge. Here, a 2D ultrathin oxygen vacancy (Ov)-rich Bi2W0.2Mo0.8O6 solid solution photocatalyst is designed and fabricated to tackle the dilemma through component and structure optimization. Specifically, the construction of a solid solution with ultrathin structure initially facilitates the separation of photoinduced electron-hole pairs, while the introduction of Ov strengthens such separation. In the meantime, the presence of Ov extends light absorption to the NIR region, triggering a photothermal effect that further enhances the charge separation and accelerates the redox reaction. As such, photoinduced charge carriers in the Ov-Bi2W0.2Mo0.8O6 are separated step by step via the synergistic action of 2D solid solution, OV, and solar heating. Furthermore, the introduction of OV exposes surface metal sites that serve as reactive Lewis acid sites, promoting the adsorption and activation of toluene. Consequently, the designed Ov-Bi2W0.2Mo0.8O6 reveals an enhanced photothermal catalytic toluene oxidation rate of 2445µmolg-1h-1 under a wide spectrum without extra heat input. The performance is 9.0 and 3.9 times that of Bi2WO6 and Bi2MoO6 nanosheets, respectively.

Tailoring the microstructure and mechanical properties of laser metal deposited Hastelloy X superalloy via heat treatment and subsequent hot plastic deformation

The laser metal deposition technology, characterized by its inherent rapid cooling rate and high thermal gradient, poses significant challenges in fabricating large-scale, complex thin-walled Hastelloy X components that necessitate precise dimensional accuracy and structural integrity. To tackle this issue, a novel compound forming process is proposed, wherein a near-net-shaped preform is produced using laser metal deposition technology, followed by shape and properties regulation through the hot metal gas forming process. This investigation systematically explores the hot formability, pre-deformed microstructure and properties of Hastelloy X superalloy sheets fabricated through laser metal deposition, aiming to identify optimized process parameters and to validate the feasibility of this advanced forming process. Results indicate that: (1) The laser metal deposited Hastelloy X superalloy, subjected to solution and aging heat treatments, demonstrates remarkable microstructural integrity and exceptional hot formability, attributed to its pronounced overall crystalline texture and minimal dislocation density. (2) The optimal processing domain was established within a temperature range of 900 °C to 1000 °C and a strain rate of 0.001 s−1, as derived from hot processing maps based on dynamic material model. (3) Pre-deformation at 950 °C facilitates uniform and stable precipitation of nanoscale M23C6 carbides and the formation of a high-density dislocation network, significantly enhancing strength. Overall, through appropriate heat treatment and subsequent hot plastic deformation, the microstructure of Hastelloy X superalloy was optimized, yielding exceptional mechanical properties at both room and elevated temperatures. The feasibility of forming laser metal deposited preforms using the hot metal gas forming process was confirmed, laying a foundation for the future application of this innovative process. The methodologies and insights derived from this research are particularly relevant to the fabrication of large-sized, complex thin-walled components, especially within demanding aerospace applications and next-generation transportation systems.

B1914 Ni-Based Superalloy Properties After Solution Heat Treatment and Long-Term Exposure at High Temperature

B1914 Ni-Based Superalloy Properties After Solution Heat Treatment and Long-Term Exposure at High Temperature

Microstructure and mechanical properties at elevated temperatures of as-built and heat-treated Inconel 718 produced through laser powder bed fusion processes

Purpose This study aims to better understand the influence of various post-treatments on the microstructure and mechanical properties of additively manufactured parts for critical applications. Design/methodology/approach In this study, Laser Powder Bed Fusion (LPBF) fabricated Inconel 718 (IN718) samples were subjected to various heat treatments, namely homogenization, solution heat treatment and double aging, to investigate their influence on the microstructure, mechanical properties and fracture mechanism at an elevated temperature of 650 °C. Homogenization treatment was performed at 1080 °C for durations ranging from 1–8 h. The solution treatment temperature varied from 980 °C to 1140 °C for 1 h, followed by double aging treatment. Findings At 650 °C, the as-built sample showed the minimum strength but demonstrated the maximum elongation to failure compared to the heat-treated samples. The strength of the IN718 superalloy increased by 20.26% to 34.81%, while ductility significantly reduced by 65.26% to 72.89% after various heat treatments compared to the as-built state. This change is attributed to the enhancement in grain boundary strength resulting from the pinning effect of the intergranular δ-phase. Originality/value The study observed that the variations in the fracture mechanism of LPBF fabricated IN718 depend on the duration and temperature of heat treatment. This research provides a thorough overview of the high-temperature mechanical properties of LPBF fabricated IN718 subjected to different homogenization times and solution treatment temperatures, correlating these effects to the corresponding changes in microstructure.

Effect of Heat Treatment on Mechanical Characteristics and Microstructure of Aluminium Alloy AA6061

Aluminium alloy 6061 (AA6061) is widely used across various industries. It has untapped potential in diverse sectors due to its exceptional strength, lightweight characteristics and corrosion resistance. It finds value in aerospace, automotive, marine, sports gear, architecture, renewable energy, electronics, healthcare devices, packaging and defence. This study investigates the impact of heat treatment on AA6061 on its microstructural and mechanical properties (tensile strength and microhardness). The main goals of this study involve assessing the mechanical properties of AA6061 after subjecting it to solution heat treatment at various temperatures and time intervals. Furthermore, the study aims to understand the relationship between microstructural alterations and mechanical properties in AA6061 following heat treatment. A combination of tensile tests, hardness tests, and scanning electron microscopy (SEM) to examine the material's microstructure. The findings reveal that the sample subjected to the heat treatment of 450°C for 60 minutes exhibited the highest tensile strength, boasting an impressive 130.9 MPa, coupled with a remarkable hardness of 19.8 HRB. Conversely, the sample treated at 550°C for 60 minutes displayed the most significant elongation percentage, reaching a remarkable 46%. These results can be explained by analysing the microstructure. Finer grain boundaries led to increased tensile strength and hardness, while a larger dendritic microstructure was linked with lower tensile strength and hardness. Remarkably, the second one led to higher elongation percentages. Therefore, precise control of the heating temperature and duration is crucial to enhance the performance of aluminium alloy, AA6061. With continuous research, alloy improvement and creative design, AA6061 have the potential to enhance performance and efficiency in these areas, driving technological advancements and better products.

Enhancement of the Electrical Conductivity and Mechanical Properties of Al-Mg-Si and Al-Mg-Zn Ternary Systems After a T8 Heat Treatment

The present research focuses on enhancing the mechanical properties and the electrical conductivity of alloys corresponding to the Al-Mg-Zn (two different compositions) and Al-Mg-Si systems, compared with the commercial 6201-T8 and 1350-H16 alloys, by using a novel approach based on T8 tempering (solution heat treated, cold worked, then artificially aged). After T8 tempering, the Al-Mg-Zn and Al-Mg-Si alloy systems show a better combination of electrical and mechanical properties, with an enhancement of the electrical conductivity by about 2.8% compared to that of 1350 alloy and 13% higher than for the 6201 alloy series. All studied alloys exhibit better mechanical properties than 1350-H16 and are similar to those of 6201-T8.

Influence of solid solution time on microstructure and precipitation strengthening of novel maraging steels

Effective subsequent heat treatment is crucial for achieving the desired microstructure and excellent mechanical properties in laser-deposited high-performance maraging steel. In this paper, we systematically investigate the synergistic relationship and tuning mechanism of different solution treatment times on the microstructure-property synergy of new maraging steels fabricated using laser direct energy deposition (LDED). To determine the optimal heat treatment process, solution treatment was conducted at 840 °C for varying durations, followed by aging at 530 °C for 2 h to induce precipitation strengthening. The results indicate that after 2 h of solution treatment, the alloy exhibits optimal ductility with an elongation of 7.90 % ± 0.15 %, attributed to the refinement of the martensitic matrix and precipitated phases, along with the formation of a small amount of residual austenite. When the solution treatment time is extended to 4 h, the alloy achieves its highest tensile strength, reaching 1958 ± 24 MPa. However, the elongation decreases to 7.31 % ± 0.12 % due to the coarsening of the martensite and secondary phase particles. After 6 h of solution treatment, significant coarsening and aggregation of the martensite and Fe2Mo intermetallic compounds markedly reduce the hardness, strength, and toughness of the alloy. By adjusting the solution treatment time, the size, morphology, and distribution of the martensitic matrix, Fe2Mo, and nanoscale precipitated phases play a critical role in the strengthening and fracture processes. Therefore, optimizing the precipitation behavior of the martensitic matrix and Fe2Mo intermetallic compounds through rational solution heat treatment is key to enhancing the mechanical properties of laser-deposited new maraging steels.