Thermal Coefficient Of Resistance Research Articles

The Thermal Properties of a Prototype Insulation with a Gyroid Structure-Optimization of the Structure of a Cellular Composite Made Using SLS Printing Technology.

This paper focuses on the search for novel insulating structures, and the generation of them by means of a state-of-the-art manufacturing method—3D printing. Bionic structures, which are successfully used in many branches of technology, were chosen as the source of inspiration for the research. The paper presents a design of spatial structures with a gyroid infill (e.g., TPMS), the shape of which reflects the bionic structure of the inside of a bone. For SLS printed single- and multi-layered structures, the design value of the thermal conductivity coefficient was determined through measurements and calculations. A statistical analysis was carried out to determine the effect of the direction of heat flow, as well as the internal structure and layering of the prototype materials, on the values of the thermal conductivity coefficient and the thermal resistance coefficient. On the basis of the multicriteria analysis, the composite’s optimal composition according to the adopted optimization criteria was determined. The lowest possible thermal conductivity of the insulation was equal to 0.033 W/(m·K). The highest possible thermal resistance was equal to 0.606 m2·K/W. Thermal insulation made of the prototype insulating partitions with a gyroidal structure is characterized by good insulating parameters.

Reduced graphene oxide temperature sensor via photo-thermal laser irradiation for a printed circuit board

We report thermal behavior of reduced graphene oxide (rGO) as temperature sensor patterned on a ready-made printed circuit board (PCB). Solution-processable graphene oxide (GO) was drop-casted and reduced by photo-thermal laser irradiation directly on PCBs. Laser irradiation adjusted for appropriate light power reduced GO without destroying electrode patterns and electronic components in PCBs, causing rGO to become a negative thermal coefficient of resistance (TCR). The rGO sensor with electrodes improved contact resistance showed 46% temperature variation from −10 °C to 90 °C. Furthermore, the rGO sensor was fabricated between analogue pin electrodes of commercial Arduino PCBs to measure temperature. An Arduino system showed 13.1% sensitivity to temperature variation from −10 °C to 50 °C detected at the analogue input pin of rGO sensor.

COMPARATIVE ANALYTICAL DETERMINATION OF THERMAL PROTECTION BEHAVIOR FOR EXPERIMENTAL MODELS MADE OF STRATIFIED BIOCOMPOSITE BOARDS OF LIGNO-CELLULOSE NATURE

The paper addresses the comparative analytical determination of thermal insulation behavior for various experimental models made of stratified and hybrid biocomposites of ligno-cellulose nature. The analytical determination of the thermal resistance and the overall thermal insulation coefficient for each experimental model is performed using the calculation methodology for energy efficiency. The results obtained after the analysis of the thermal insulation behavior for the biocomposite panels highlighted the fact that they have thermal insulation properties with high values for thermal resistance and global thermal insulation coefficients.

Thermal performance prediction of heat pipe with TiO2 nanofluids using RSM

Heat pipe is a two-phase heat transfer device with high effective thermal conductivity and transfer huge amount of heat with minimum temperature gradient in between evaporator and condenser section. This paper objective is to predict the thermal performance in terms of thermal resistance, R, and heat transfer coefficient, h, of screen mesh wick heat pipe with deionized water-TiO2 as working fluid. The input process parameters of heat pipe such as heat load, Q, tilt angle, ?, and concentration of nanofluid, ?, were modeled and optimized by utilizing response surface methodology with MINITAB-17 software to attain minimum thermal resistance and maximum heat transfer coefficient. The minimum thermal resistance of 0.1764 ?C per W and maximum heat transfer coefficient of 1411.52 W/m2 ?C was obtained under the optimized conditions of 200 W heat load, 57.2? tilt angle, and 0.159 vol.% concentration of nanofluid.

Steady-state stability improvement of reduced graphene oxide thermo behavior via polymer film encapsulation

We report steady-state stability improvement of reduced graphene oxide (rGO) thermo behavior via polyimide (PI) film encapsulation. A temperature sensor was made of rGO produced by photo-thermal laser irradiation of graphene oxide (GO) and showed a negative thermal coefficient of resistance (TCR). However, when the rGO-based temperature sensor was exposed to air, the resistance increased owing to the attachment of an oxygen-containing molecule, particularly water molecules on the surface of the rGO. To solve this issue, the surface of rGO was encapsulated with a PI film, and the encapsulated temperature sensor showed significant stable resistance characteristics at 25 °C and 40% relative humidity for seven days compared to bare rGO while retaining the sensitivity of the sensor. Scanning electron microscopy images confirmed that most of the rGO surface was separated from the encapsulated PI layer, and the morphology of the rGO surface remained intact, thus maintaining the temperature variation properties without being affected by external humidity. In addition, the PI-encapsulated rGO produced a thermoacoustic sound of 78 dB at 5 kHz performance after 30 days.

Multiobjective optimization for the optimal heat pipe working parameters based on Taguchi's design of experiments

AbstractA heat pipe (HP) is a device transferring large quantities of heat through a small area of the cross‐section with very small deviations in temperature. The thermal impedance of HP is lower while thermal conductance is higher. HPs are designed for controlling temperature, amplification of heat flux, and diminution. HPs are being used in the cooling of aircraft and electronics, solar energy, systems of heat recovery, and nuclear reactors. Complex mathematical formulation demands experimentation to acquire the physical phenomena. Performing experiments is a tedious task with increasing the working parameters and their assigned levels. In such situations, a systematic statistical approach (viz., the Taguchi method) has to be adopted to minimize the number of experiments and to provide the information for the full factorial design of experiments. This paper adopts the modified Taguchi method and applies a simple and reliable multiobjective optimization concept to determine the optimal HP working parameters (viz., heat input, inclination angle, and flow rate). In the optimization process, efficiency, thermal resistance, and overall heat transfer coefficient are the performance indicators (PIs). Empirical relations are developed and validated for the PIs in terms of the HP working parameters. The recommended Taguchi's orthogonal array to perform a few tests may not have the set of optimal working parameters. Additional tests are to be performed to confirm the estimates of the PIs for the optimal working parameters. Confirmation test results in the present study indicate close‐to/within the estimated range.

Influence of metallo-dielectric optical properties on thermal resistance and solar heat gain coefficient of multi-pane glazing systems in hot and cold climates

ABSTRACT The design of efficient windows and building facades in relation to their energy-saving potentials can be developed through an advanced computational modeling analysis, and thus an effective basis of comparison of the thermal performance of glazing systems can be realized. This study simulates the behavior of window systems that integrate partitioning radiant shades, where the latter are situated between typical glass panes comprising an insulated glazing unit. The partitioning shades comprise of spectrally selective metallo-dielectric coatings that modulate optical transmittance in the visible, infrared and mid-infrared regions. Wide variety of window configurations are studied, and the results are analyzed based on the system performance criteria of thermal resistance (R-value and U-value) and solar heat gain coefficient. The comparative performance assessment of single, double, triple and quadruple ‘pane’ glazing systems in relation to internal and external environmental conditions is presented. The effects of different parameters such as fill gas, inter-pane distance, pane thickness and optical properties of coatings on thermal behavior of the fenestration system are presented. Optimal design parameters for cold and hot climates are proposed; and the results show that it is possible to reduce up to 90% heat loss in winter for the most effective configuration.

Investigation the influence of spacer yarns orientation angle on the thermal behavior of 3D textile reinforced concrete (TRC)

Thermal behavior such as heat transfer is an important parameter for construction composites. Three-dimensional textile reinforced concrete (TRC) is one of the construction composites which is recently being used in the building industry. Therefore, in this study, the thermal behavior of three different TRC samples was investigated by a heat transfer test using an infrared method. The cementitious matrix was reinforced by 3D fabric with three different spacer yarn orientation angles. The cementitious matrix was fabricated by cement and waste stone powder. The TRC sample was put on the hot plate of the heat transfer apparatus and the temperature variations of the top surface of the sample were obtained. According to the test results, increasing the orientation angle of spacer yarns leads to a decrease in the thermal conductivity of the TRC sample and reduces heat transfer. On the other hand, a theoretical model was used to calculate the thermal conductivity and resistance coefficients of sandwich samples. Furthermore, a 3D finite element model was used to predict the heat transfer of TRC specimens. A unit cell of the TRC model was created in Abaqus software and finite element (FE) analysis was carried on a created model. Thermal conductivity and thermal resistance of samples according to FE results were calculated and compared with experimental results. FE results showed good agreement with the experimental data.

(Invited) Understanding Self-Heating in FinFETS and Its Impact on Metal Interconnect

Self-Heating (SE) in FinFETs can be of significant concern for reliability of back-end-of-line (BEOL) interconnects due to electromigration (FM) failure, which is a highly sensitive degradation mechanism at elevated temperatures (1, 2). Temperature levels of ≥5°C due to front-end-of-line (FEOL) self-heating at M1 lines can impact the circuit’s reliable operation (3). The confined heat due to self-heating in FinFETS can flow vertically and laterally to the local interconnects and increasing the metal temperature thereby accelerating the EM failure rate probability. Furthermore, while FinFETs provide the performance, power and scaling advantages over planar devices the local self-heating can potentially affect device performance and exacerbate the effects of various reliability mechanisms (4). It is, therefore, imperative to understand the quantification of self-heating in FinFETs and its reliability implications in the devices, circuits and metal interconnects.In this presentation we will discuss several experimental methodologies to quantify SH using wafer level measurements by implementing three different types of electrical sense elements. The sensing schemes evaluate the surround heat sensing using the electrical characteristic of a neighboring FET device and a local heat sensing element using a 4-terminal kelvin contact to measure the thermal coefficient of resistance of the metal gate. We will evaluate the proximity and effectiveness of these sense elements. We will also investigate the impact of SH on logic circuits using a simple ring-oscillator circuit. The characteristics will be validated through predictive thermal simulations. From the results it is inferred that dense circuit applications such as clock buffers are required to be studied more carefully for its impact of self-heating on upper metal lines. This is particularly critical for technologies such as SOI FinFETs where heat generated by frontend-of-line devices is being forced through the upper metal lines due to the buried oxide where self-heating impact is 5x higher compared to bulk FinFET technology.The author acknowledges the collaborators of Globalfoundries, especially Dr. Peter Paliwoda, for the technical discussion.References W. Chang, S.E. Liu, B.L. Lin, C.C. Chiu, Y.-H. Lee and K. Wu, IEEE IRPS, 2F.6.1, (2015).S-W. Yoo, H. Kim, M. Kang, and H. Shin, of Semicon. Tech and Sc, vol.16(2), 204, (2016).Peter Paliwoda, Doctoral Dissertation, https://digitalcommons.njit.edu/dissertations/1389, NJIT, 1389, pp. 96, (2018).Paliwoda, Z. Chbili, A. Kerber, T. Nigam, K. Nagahiro, S. Cimino, M. Toledano-Luque, L. Pantisano, B.W. Min, and D. Misra, IEEE Trans. on Dev. and Mat. Reliability, vol. 19(2) (2019).

Investigating Branched Polyethylene Sensors for Applications in Prosthetics

AbstractThere is a need for new conductive, scalable sensors with piezoresistive and thermoresistive properties for applications in bioengineering. For example, the demand for real‐time sensory feedback in upper‐limb prosthetics requires sensors that are low‐cost, scalable, and sensitive to temperature, pressure, and movement. It is possible to manufacture low‐cost conductive sensors by directly mixing a low‐cost filler such as graphite into fillers such as polyorganosiloxane, although they can have poor electrical and mechanical homogeneity. In this paper, an alternative approach is outlined to form these sensors: ethylene was polymerized using a nickel catalyst to form a polymer with up to 93 branches per 1000 carbon atoms. This branched polyethylene was fibrous and had a greater volume than high‐density polyethylene. After hot pressing with a graphite filler to form a conductive, flexible sensor, the polyethylene samples had electrical resistivity down to 0.067 m, a thermal coefficient of resistance −7.5 at 27 , and a electrical resistance sensitive to forces down to 0.1 N. The process is scalable, and provides a route to homogeneous, low‐cost sensors for future prosthetics applications.

Energetic refurbishment of the historic windows of the listed heritage building Alte Schäfflerei and its influence on the overall energy balance

This study examines compatibility of monument conservation and modernization of historic windows of old buildings on the example of the Alte Schäfflerei (Old Cooperage) housing the Fraunhofer Centre for Conservation and Energy Performance of Historic Buildings at Benediktbeuern monastery. Several historic windows are extended to box-type windows and examined in detail. The calculation of the thermal bridges and the resulting U-values of the windows as well as the linear thermal bridge heat loss coefficients result in a reliable estimation of the thermal behaviour of the box-type windows. Via measurements of the surface temperature and heat fluxes on a box-type window the thermal resistance and heat transfer coefficient are estimated. The heat transfer coefficient is calculated in accordance to DIN 10077 with simple and detailed calculation and compared to the estimated calculation of simplified measurements. The energy efficiency of the whole building of the Old Cooperage is calculated in accordance to DIN V 18599 and shows the rate of heat losses of the windows compared to the overall energy demand of the building. For this purpose, the Old Cooperage is implemented with a hypothetical historic usage in DIN V 18599.

Modelling evaporation in electron-beam physical vapour deposition of thermal barrier coatings

This work presents computational models of ingot evaporation for electron-beam physical vapour deposition (EB-PVD) that can be applied to the deposition and development of thermal barrier coatings (TBCs). TBCs are insulating coatings that protect aero-engine components from high temperatures, which can be above the component’s melting point. The development of advanced TBCs is fuelled by the need to improve engine efficiency by increasing the engine operating temperature. Rare-earth zirconates (REZ) have been proposed as the next-generation TBCs due to their low coefficient of thermal conductivity and resistance to molten calcium-magnesium alumina-silicates (CMAS). However, the evaporation of REZ has proven to be challenging, with some coatings displaying compositional segregation across their thickness. The computational models form part of a larger analytical model that spans the whole EB-PVD process. The computational models focus on ingot evaporation, have been implemented in MATLAB and include data from 6 oxides: ZrO2, Y2O3, Gd2O3, Er2O3, La2O3 and Yb2O3. Two models (2D and 3D) successfully evaluate the evaporation rates of constituent oxides from multiple-REZ ingots, which can be used to highlight incompatibilities and preferential evaporation of some of these oxides. A third model (local composition activated, LCA) successfully predicts the evaporation rate of the whole ingot and replicates the cyclic change in composition of the evaporated plume, which is manifested as changes in compositional segregation across the coating’s thickness. The models have been validated with experimental data from Cranfield University’s EB-PVD coaters, published vapour pressure calculations and evaporation rate formulas described in the literature.

Heat Resistance of Steel N8G6M3FTB Obtained by Surfacing Cored Wire

The operational reliability of rolling production tools depends on the heat resistance of the steel from which they are made. To increase the performance of the rolls, a hardening surfacing with wear-resistant alloys is used. The effectiveness of the applied hardening technology depends on the functional characteristics of the deposited metal. The aim of the work is to study the tempering resistance in the state after heat treatment of the deposited steel (Fe-C-Ni-Mn-Mo-V-Ti-Nb system). It was established that the thermal resistance coefficient of steel 15N8G6M3FTB at temperatures from 650 to 800 °C varies from 0.76 to 0.66, which exceeds the heat resistance of steel 30Kh2V8F by 1.5 times. It is shown that in the fine structure of such a metal after tempering at 800 °C, large amounts of finely dispersed precipitates are observed. These precipitates have a rounded shape up to 100 nm in size and belong to the Laves phases - Fe2Mo, Fe2Nb, and Fe2Ti. The obtained high heat resistance values of 15N8G6M3FTB steel make it possible to recommend it for creating surfacing materials. Flux-cored wire based on this steel can be used for hardfacing hardening of tools operating at temperatures up to 800 °C inclusive.

A thermal cracking pattern-based multiscale homogenization method for effective thermal conductivity of steel fiber reinforced concrete after high temperature

The mesoscopic thermal cracking behavior in steel fiber reinforced concrete (SFRC) caused by high-temperature load can result in a substantial reduction of effective thermal conductivity (ETC) at macroscale level. In this study, a multiscale homogenization method for identifying the ETC of thermally damaged SFRC is proposed. This new method is characterized by the consideration of crack thermal resistance effect rather than using temperature-dependent thermal conductivities of components in cementitious composite. A series of experiments on thermal conductivity of mortar, plain concrete, and SFRC heated at various temperatures is performed. The method predictions satisfy the experimental results extremely well when the interfacial thermal resistance (ITR) coefficient is assumed to increase linearly with temperature. The numerical and experimental results show that the ITR effect makes approximately 50%, 36%, and 7%–12% contributions to the overall thermal conductivity reductions in the mortar, plain concrete, and SFRC heated up to 600 ∘C, respectively. Moreover, it is found that the trend and magnitude of ETC reduction caused by heating increase with the increase in particle content and particle-matrix thermal conductivity ratio due to the synergistic effect of heat bridge and ITR.

Axisymmetric thermoelastic deformation of a multilayer plate with imperfect thermal contact of its layers

An axisymmetric stationary problem of thermoelasticity for a multilayer plate with imperfect thermal contact between its layers is solved by using the method of compliance functions along with the Hankel transform. It is assumed that the conditions of perfect mechanical contact are satisfied on their common boundaries. The Hankel transforms of displacements, stresses, and temperature at the points of the layer can be represented in the form of the linear combinations of the six auxiliary functions. The auxiliary functions are connected with the Hankel transforms of displacements, stresses, temperature and flow at the points of the upper boundary of the corresponding layer. For the problem considered six auxiliary functions can be found from the boundary conditions. Using the conditions on the common boundaries of the layers and entering a dummy layer the recurrent formulas for finding other auxiliary functions are constructed. The auxiliary functions of each layer are dependence. This dependence is represented in the matrix form using so-called compliance functions. The recurrence relations for the compliance functions of the thermoelastic multilayer plate are constructed. The algorithm for solving the сonsidered problem is formulated. The numerical calculations are made for a two-layer plate subjected to the action of the thermal loads. The influence of the coefficient of thermal resistance on the distribution of temperature at the points of the lower boundary of the upper layer and at the points of the upper boundary of the lower layer is analyzed. Also the influence of this coefficient on the distribution of normal stresses at the common boundary of layers is analyzed.

Effect of ZnO Addition on Effective Fracture Energy of Alumina-Magnesia Castable Refractory

Alumina-magnesia castable refractory is used for the inner wall of molten steel ladle. The main cause of damage to this refractory is thermal shock caused by a sudden temperature change when putting in and out molten steel. Therefore, there is a thermal shock damage resistance coefficient R'''' as a parameter that represents the resistance of refractory materials to thermal shock, and the evaluation of effective fracture energy is important for improving R''''. The purpose of this study is to evaluate the effect of ZnO addition on the effective fracture energy of alumina-magnesia castable refractories. ZnO is reported to improve the mechanical properties of spinel (MgAl2O4). Samples containing 0 to 3 mass% ZnO were prepared, and the effective fracture energy, crystalline phase, microstructure, and apparent porosity were evaluated. The effective fracture energy increased with the increase of the amount of ZnO added. The apparent porosity shows a constant value regardless of the amount of ZnO added, and the promotion of spinel sintering and the increase of spinel amount by the solid solution of zinc oxide contributed to the improvement of the effective fracture energy.

Study on Properties of Mg-Al Spinel Ceramics Prepared by Casting Sintering Method

Magnesium alumina spinel (MgAl2O4) is a composite mineral composed of MgO and Al2O3, and its theoretical chemical composition is 28.33 wt% MgO and 71.67 wt% Al2O3, with excellent properties such as high melting point, high hardness, high strength, high resistivity, wide energy band gap, low coefficient of thermal expansion, corrosion resistance and thermal shock. In the process of synthesizing magnesia-alumina spinel ceramics, it is important to select suitable sintering temperature, suitable holding time, suitable kinds of mineralizers and suitable amount of mineralizers in order to improve the strength and toughness of magnesia-alumina spinel ceramics and reduce the water absorption of magnesia-alumina spinel ceramics. In this study, using fused magnesia powder and alumina powder as main raw materials, sodium hexametaphosphate as water reducer, silica powder as binder and titanium dioxide powder as mineralizer, magnesia-alumina spinel ceramics were synthesized by casting and sintering. The effects of sintering temperature and holding time on the properties of magnesia-alumina spinel ceramics were studied. The most suitable sintering temperature is about 1600 °C and the most suitable holding time is about 4 h. Titanium dioxide powder was selected as mineralizer, and the effect of adding titanium dioxide powder on the properties of synthesized magnesia-alumina spinel ceramics was studied. The experimental results show that the addition of titanium dioxide powder can improve the bending strength and reduce the water absorption of the synthesized magnesia-alumina spinel ceramics. When the addition of titanium dioxide powder increased to 7%, the bending strength of magnesia-alumina spinel ceramics increased to 33 MPa, and the water absorption decreased to 2.8%. SEM analysis shows that the addition of titanium dioxide powder can promote the formation of magnesia-alumina spinel phase, refine the grain size of magnesia-alumina spinel and strengthen the microstructure of magnesia-alumina spinel ceramics.

Obtaining and electronic emission of planar structures of metallic copper on a porous ceramic substrate

Planar structures of metallic copper are synthesized in porous glass (PG) plates by reduction of two-dimensional layers of copper (II) oxide by molecular hydrogen. The stability and electrical conductivity of the formed copper ensemble, close to the monolayer, are achieved when it fills the surface of the PG and is determined by the content and reduction temperature of the oxide precursor. The content of experimentally obtained copper oxide in porous glass is determined by its resistance to oxidation in air. A manifestation of the characteristic planar state of copper in porous glass is a slight slope of the dependences R(T–1). Te obtained values of the thermal coefficient of resistivity are in the range of 0.0005÷0.0008 degrees–1, which corresponds to values smaller than ones for bulk copper (0.004 degrees–1). Therefore, the formation of dielectric gaps resulting from the incomplete oxidation process for the twodimensional copper layer leads to an increase in the resistance while maintaining the adjacent sections, which in this case determine the nature of the conductivity, similar to metals. The occurrence of emission from the surface of Cu/PG systems is observed at values of the electric field strength less than 2 V/μm, decreasing in a narrow range when the copper content exceeds the conditional monolayer.The work was carried out within the framework of the state task with the financial support of the Ministry of Education of the Russian Federation (project No. FSZN-2020-0026).

Analysis of newborn thermal comfort in a textile incubator

Data published by European and World Health Organizations show that since 1990 the number of births has been steadily decreasing, which poses the risk of lack of generational replacement. According to WHO report, every year, 2.6 millions of newborns in the world die in the first month of their life. One million of them in the first 24 h so they require special care and medical supervision, so for the first days or even months of their lives they remain in incubators. The purpose of the research was to develop the construction and build a prototype of a textile incubator, whose most important function is to keep the baby warm, with the possibility of cooling it during therapeutic hypothermia. The incubator model was built in three variants of material packages, and each of them consisted of five material layers. An innovative solution is using for the external thermal insulation layer a composite connecting a knitted fabric with aerogel. The total thermal conductivity resistance for the developed material packages of the incubator was measured using a thermally insulated sweating hot plate known as the ‘skin model’. The obtained values of thermal resistance coefficient R ct are within 2.07–2.83 clo, and in case of the package with an additional insulation layer R ct = 3.68 clo. It turned out that when the infant was placed in a textile incubator without a functional heating and cooling mat its heat balance for the adopted ambient temperatures from −5 to 24 °C was negative and ranged from −0.04 up to −50.50 W. In cases of positive heat balance, especially for all ambient temperatures, which took place for the second package where ΔQ = 0.10 ÷ 6.51 W, there is a risk of overheating the baby. The analysis of the heat balance components shows that convection and radiation have the greatest impact on the total heat loss, as on average they constitute 85.6% of the heat lost by a baby in a textile incubator.

Tailoring grain sizes of the biodegradable iron-based alloys by pre-additive manufacturing microalloying

We demonstrated the design of pre-additive manufacturing microalloying elements in tuning the microstructure of iron (Fe)-based alloys for their tunable mechanical properties. We tailored the microalloying stoichiometry of the feedstock to control the grain sizes of the metallic alloy systems. Two specific microalloying stoichiometries were reported, namely biodegradable iron powder with 99.5% purity (BDFe) and that with 98.5% (BDFe-Mo). Compared with the BDFe, the BDFe-Mo powder was found to have lower coefficient of thermal expansion (CTE) value and better oxidation resistance during consecutive heating and cooling cycles. The selective laser melting (SLM)-built BDFe-Mo exhibited high ultimate tensile strength (UTS) of 1200 MPa and fair elongation of 13.5%, while the SLM-built BDFe alloy revealed a much lower UTS of 495 MPa and a relatively better elongation of 17.5%, indicating the strength enhancement compared with the other biodegradable systems. Such an enhanced mechanical behavior in the BDFe-Mo was assigned to the dominant mechanism of ferrite grain refinement coupled with precipitate strengthening. Our findings suggest the tunability of outstanding strength-ductility combination by tailoring the pre-additive manufacturing microalloying elements with their proper concentrations.