Cast Samples Research Articles

Effect of build orientation on wear and erosion behavior of maraging steel processed by powder bed fusion using laser beam (PBF-LB)

The wear and erosion behavior of additively manufactured maraging steel with built orientations of 0°, 45° and 90° were investigated and compared with conventional (cast and hot rolled) samples. To investigate the effect of heat treatment, processed samples were subjected to solution treatment and ageing. As-built (AB) and heat-treated (HT) samples were wear-tested at various loads of 20N, 40N and 80N, at constant disc speed and specific sliding distance. Erosion tests were performed at 90° impingement angle for 40 min with erosion discharge rate of 4.5 g min−1, wear rate was found increasing with the increase in load from 20N to 80 N, and was found affected by build orientation, mainly in the as-built additive samples. In both, as built as well heat-treated conditions, 90° oriented samples were found more wear-resistant. However, wear resistance of the heat-treated samples was observed to be relatively higher as compared to that of as-built samples. Coefficient of friction (COF) decreased with increase in load, in both as built as well heat-treated conditions. Erosion resistance of the as-built (AB) and heat-treated (HT) samples in 0° orientation was higher than that of other build orientations. Prior to heat treatment, erosion resistance of the conventional samples was inferior to that of additive samples, due to comparatively coarser microstructure; however, after the heat treatment, erosion resistance was increased. Worn and eroded samples were examined under SEM and AFM. At low load of 20 N, abrasive wear by ploughing and at high load of 80N, adhesive wear was noticed. Erosion occurred mainly by lip formation and plastic deformation.

Hydration products, pore structure, and compressive strength of extrusion-based 3D printed cement pastes containing nano calcium carbonate

While interest in extrusion-based 3D concrete printing technology has been growing in recent years, only limited literature investigates the hydration products and pore structure of 3D printed cementitious materials (3DPC). The microstructure and compressive strength results of 3D printed cement paste with and without nano calcium carbonate (NC) were investigated and compared to conventionally cast cement pastes. Herein, all mixes possess approximately the same static yield stress, which was adjusted by an additional polycarboxylate superplasticizer (SP). The compressive strength test was employed to quantify the mechanical anisotropy of samples. The hydration products and microstructure of samples were evaluated at 7 days using X-ray diffraction (XRD), scanning electron microscopy (SEM), and backscattered electron image (BSE) analysis. The results demonstrate that 3D printed cement paste showed a lower compressive strength than cast cement pastes in all directions. The intense and sharp calcium hydroxide (CH) peaks were seen in the XRD analysis of the 3D printed sample, which suggested its high crystallinity. The large size of plate CH can be observed in SEM images. These results indicate that CH grains in 3D printed samples have enough space to grow due to the relatively loose microstructure. This observation was confirmed by the porosity of the 3D printed sample analyzed by BSE images. The BSE imaging analysis also showed that the pore size distribution of the 3D printed sample was different from that of the cast sample. Additionally, the interfacial transition zone (ITZ) in the 3D printed sample presented a looser microstructure than the cast sample. Therefore, the reduced compressive strength of 3D printed cement pastes is the relatively loose microstructure, high porosity, and weak ITZ between unhydrated clinkers and hydration products.

Approach to Estimate the Phase Formation and the Mechanical Properties of Alloys Processed by Laser Powder Bed Fusion via Casting.

A high-performance tool steel with the nominal composition Fe85Cr4Mo8V2C1 (wt%) was processed by three different manufacturing techniques with rising cooling rates: conventional gravity casting, centrifugal casting and an additive manufacturing process, using laser powder bed fusion (LPBF). The resulting material of all processing routes reveals a microstructure, which is composed of martensite, austenite and carbides. However, comparing the size, the morphology and the weight fraction of the present phases, a significant difference of the gravity cast samples is evident, whereas the centrifugal cast material and the LPBF samples show certain commonalities leading finally to similar mechanical properties. This provides the opportunity to roughly estimate the mechanical properties of the material fabricated by LPBF. The major benefit arises from the required small material quantity and the low resources for the preparation of samples by centrifugal casting in comparison to the additive manufacturing process. Concluding, the present findings demonstrate the high attractiveness of centrifugal casting for the effective material screening and hence development of novel alloys adapted to LPBF-processing.

Investigation into the Effect of Rice Husk Ash in Partial Replacement of Cement in Concrete

The purpose of this study was to investigate the properties of Rice Husk Ash (RHA) as a partial cement replacement material in concrete production based on analysis of its contribution to strength in comparison with Ordinary Portland Cement (OPC). The analysis was focused on: the chemical properties of RHA, workability, density, compressive strength, and tensile strength of concrete. The RHA was obtained from Mwea, Kirinyaga County, Kenya and burned in a kiln to produce white ash which was tested. Chemical analysis to determine the pozzolanic properties of RHA was done using the Gravimetric method, Flame Photometry and Atomic Absorption Spectroscopy while particle size distribution of RHA was carried out using sieve analysis and hydrometer analysis. Concrete mixes with different ratios of OPC to RHA binder were cast into cuboid and cylindrical samples. The binder was made by replacing OPC with RHA at intervals of 10% by mass to a maximum of 50% replacement. A binder, sand, and ballast ratio of 1:1.5:3 were maintained with a constant water-cement ratio of 0.6. The cast samples were subjected to water curing on the third day at room temperature. Workability tests were performed on fresh concrete while compressive strength tests and tensile strength tests were performed on hardened concrete in all the mixes. The results were compared with OPC concrete. Results indicated that Kenyan RHA has high silica, alumina, and iron oxide content of about 92%. The workability slightly improves with 10% partial replacement of OPC with RHA but decreases with further addition of RHA. It was also deduced that the optimal binder mix was 10% partial replacement of OPC with RHA however the compressive strength was lower than the OPC concrete by 2.3%. The tensile strength of concrete increased with the addition of RHA up to an optimum of 10%.

Effect of Ti and TiC additions on the microstructure and wear resistance of high chromium white irons produced by laser directed energy deposition

Laser directed energy deposition (L-DED) is an additive technology that offers a rapid solution for repairing mining components made of High Chromium White Iron (HCWI) on site. However, the refined carbide morphology from the rapid cooling in L-DED is detrimental to the wear resistance of the repairs. In this study, two types of powder (Ti powder and TiC powder) were added to improve the wear resistance of L-DED HCWI. The Ti powder addition promoted the formation of in-situ TiC while the TiC powder addition resulted in coarse ex-situ TiC and fine in-situ TiC in the as-deposited microstructure. The addition of both powders destabilised the austenitic matrix (γ-Fe). The wear resistance was investigated by a high stress abrasion test using silica sand (softer than M7C3) and a pin-on-disk wear test using a ruby pin (significantly harder than M7C3). The best wear results were achieved with 6.55 wt% Ti powder addition. This destabilised γ-Fe in the as-deposited microstructure which underwent strain-induced martensite formation during the high stress abrasion wear testing, improving the wear resistance of the alloy. The addition of TiC powder improved the wear resistance in the high stress abrasion test due to the increase in the fraction of carbide. In the pin-on-disk wear test, the alloys with TiC powder addition performed better than the cast sample because a greater amount of γ-Fe matrix in the microstructure provided a better combination of hardness and ductility.

In-vitro biocompatibility evaluation of cast Ni–Ti alloy produced by vacuum arc melting technique for biomedical and dental applications

The investigated cast Ni50–Ti50 shape memory alloy was prepared using a vacuum arc furnace. The cast samples were subjected to in-vitro biocompatibility studies according to ISO 10993-12:2004, and compared to other samples Ni–Ti orthodontic wires commercially available at the dental market. The cast samples were hydroxyapatite-coated using the electrodeposition technique. The effect of surface treatment on the coating quality was addressed. The hydroxyapatite-coated samples were investigated using electrochemical impedance (EIS) and potentiodynamic techniques. Coated samples were also examined using a scanning electron microscope to inspect the coating morphology. Cytotoxicity tests on MG63 and H9C2 cell lines showed the safety and biocompatibility of the cast NiTi alloy, with a direct relationship between the incubation period of the tested samples and cell viability. Well-adhered hydroxyapatite coating was obtained on the surface-treated NiTi samples using the electrodeposition technique. EDS analysis showed a hydroxyapatite coating having a calcium to phosphorus ratio close to that of the natural bone. Electrochemical tests indicated that the highest corrosion resistance was obtained for the uncoated samples followed by the anodized sample and finally the hydroxyapatite-coated samples due to their high porosity.

MEEHANITE SF400

Abstract Meehanite SF400 is a ferritic ductile iron that has a minimum tensile strength of 400 MPa (58 ksi) and a minimum elongation of 17%, when measured on test pieces machined from separately cast samples. This fully ferritic Meehanite grade is produced by either strict control of the raw materials during melting or by an annealing heat treatment to eliminate any pearlite formed during solidification. Meehanite SF400 is specifically designed for general engineering applications where high ductility and exceptional resistance to impact is required. It also provides maximum toughness at ambient temperatures. Compared with cast steel of similar strength, it is possible to reduce machining times by up to 25%. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on casting, heat treating, and machining. Filing Code: CI-98. Producer or source: Meehanite Metal Corporation.

Design and characterization of a novel MgAlZnCuMn low melting point light weight high entropy alloy (LMLW-HEA)

Development of high-entropy alloys (HEAs) is one of the remarkable advancements in the progress of new materials. In recent years, continuous efforts have been made to design light weight high-entropy alloys (LWHEAs) with suitable microstructure and superior properties. This paper reports the preliminary results of a study aimed at design and development of a new low melting point LWHEA (LMLW-HEA) based on AlMgZnCuMn alloy system without excessive intermetallic compounds formation. In this research, first, the initial chemical composition of the alloy was designed according to thermodynamic parameters, and then the alloy was melted in a resistance electric furnace. Since the thermodynamic indicators have been defined based on alloys containing 3d transition elements, formation of binary intermetallic compounds was predicted with the help of Midema model. To investigate the effects of cooling rate and heat treatment on the structure of the designed alloy, the molten alloy was poured into two different molds made of silica sand and steel, and both as cast samples were also heat treated. Microstructural features, mechanical properties and thermal stability of the samples were then examined. Density of the samples was measured to be less than 3.4 gr/cm3 which was very close to the theoretical density of the alloy. Structures of all the samples were complex and multi-phase and contained intermetallic (ordered solid solution) binary and ternary compounds including Mg7Zn3, MgZn2, Cu2Mg, Al2Cu, Mg32 (Al, Zn)49, Mg32Cu7Al47, Al25Mg37.5Zn37.5, and CuMgZn phases. The designed alloy was brittle under all the processing conditions. Compressive strength of the alloy reached to about 95 MPa, and its hardness was in the range of 110–120 HV. Oxidation resistance of the alloy was evaluated at a temperature about 30 °C below its solidus temperature and no weight change was observed in the sample after 14 h. It is suggested that the designed alloy is a suitable candidate for high temperature applications not involving impact or cyclic loading.

Investigation of Mechanical and Wear Properties of Al-Mg2 Si-Cu-Ni Cast Composites In As-Cast And Heat Treated Conditions

This study aims to examine the mechanical and wear properties of aluminum alloy (Al-Mg2Si-Cu-Ni) in as cast and heat-treated conditions. Sliding tribology tests were carried out via a Pin-on-disc set up. Tensile, compression and hardness experiments on as-cast and 1 hour homogenized specimens were done to evaluate the mechanical properties. Universal testing machine and Brinell hardness tester were used to conduct the tensile-compressive and hardness tests at room temperature, respectively. The microstructure evolution was analyzed by X-ray diffractometer and also scanning electron microscope. The results of wear and mechanical properties indicated that heat-treated Al-Mg2Si-Cu-Ni cast composites had superior tensile and compressive strength, wear resistance and hardness, as compared to as cast samples.

Bond behavior between steel bars and 3D printed concrete: Effect of concrete rheological property, steel bar diameter and paste coating

• The effects of the rheological property on the steel–concrete bond behavior of printed and cast samples were investigated. • The porosity at the steel–concrete interface is related to the bond strength. • The bond strength values of 3D printed samples with ribbed bars of different diameters were compared. • The rheological properties of fresh concrete for 3D printing are very significant to control the quality of reinforced 3D printed concrete. Due to the unique layer by layer deposition process of extrusion-based 3D printed concrete (3DPC), the bonding of steel bars with 3DPC differs from that with traditional cast concrete. To understand the steel-printed concrete bond behavior, this paper mainly explored the effect of preparation technologies, concrete rheological properties, steel bar diameter and paste coating on steel bars on the bond behavior between ribbed steel bars and concrete. According to pull-out test and X-ray computed tomography test, the results showed that bond strengths between 3DPC and steel bars were obviously lower than those between steel bars and cast concrete. The rheological properties of fresh concrete show significant impact on the bond behavior of reinforced 3D printed samples. Lower yield stress and plastic viscosity can narrow the bond strength gap between printed samples and cast samples. The utilization of surface coated steel bar with fresh cement paste can effectively enhance the steel-3DPC bond strength. The variations in steel–concrete bond strengths can be explained via pore structure at steel–concrete interface. The results suggest that it is of great importance to control the quality of reinforced 3D printed concrete by optimizing the rheological properties of fresh concrete for 3D printing.

Structure-property relations of lightweight Ti-Sc-Zr-Nb-V high-entropy alloys

Recently, it has been a hot topic to explore lightweight high entropy alloys (HEAs) for their future potential application as engineering materials. In this work, novel lightweight Ti 22 Sc 22 Zr 22 Nb 17 V 17 , Ti 24 Sc 20 Zr 22 Nb 17 V 17 , Ti 24 Sc 22 Zr 20 Nb 17 V 17 , and Ti 26 Sc 20 Zr 20 Nb 17 V 17 HEAs were fabricated by rapid solidification. The phase constituents and microstructures of the HEAs in the cast and annealed states were characterized by X-ray diffraction spectrum (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive spectrum (EDS), while their mechanical properties were also investigated in detail. The microstructures of the cast samples consist of the coarse equiaxed BCC dendrites with extremely heterogeneous chemical distributions and the intergranular structures that are made up of BCC and HCP precipitates. Both precipitates inside the intergranular structures exhibit slightly large worm-shaped and fine lamellar morphology features. After annealing at temperatures below 1273 K, the desolvation reaction occurs due to the strong solute redistribution, leading to the disappearance of the lamellar structures, the coarsening of the large worm-shaped BCC particles, and the solid phase separation of the equiaxed BCC dendrites. At 1273 K, the combined interaction from the eutectoid transformation and phase separation leads to the formation of the TiNbV-rich BCC, ScZr-rich HCP, and transitional BCC+HCP structures. Compared with reported lightweight HEAs (density ≤ 6.5 g/cm 3 ), the present HEAs in the cast and annealed states exhibit excellent comprehensive mechanical properties, which are attributed to the combined effect from the solid-solution strengthening, second phase strengthening, and fine-grained strengthening. The present studies provide potential candidates as lightweight high-temperature structural materials in the future. • Compositional variations and heat treatments on structure and properties of as-cast lightweight HEAs were investigated. • Phase types are well consistent with the calculation prediction. • Dendritic intergranular regions contain some worm-shaped and fine lamellar BCC particles and HCP precipitates. • Low-temperature annealing induces strong solute redistribution within BCC and HCP phases. • Annealing at 1273 K induces the eutectoid transformation and phase separation.

Evaluation of aggregates, fibers and voids distribution in 3D printed concrete

3D printed concrete technology has received a traffic attention in construction industry in recent years, due to the potential advantage: time and labor savings, cost reduction, low environmental impact. In this study, the influence of distribution of aggregate and steel fiber on the mechanical properties of 3 D printed concrete is experimentally investigated. The distribution characteristic of aggregate and steel fiber in 3 D printed concrete are evaluated by using X-ray computed tomography (X-CT) with 2 D image analysis method. The cast concrete is performed as reference. It is found that the aggregate and fiber in cast concrete are relatively evenly distributed and no alignment, while there is an orientation probability of more than 40% for aggregate, and 74% for fiber, respectively, along the printing direction in ± 20° in printed concrete. Meanwhile, using X-CT, the porosity, void sizes, shapes and distributions in printed and cast concrete are also investigated. Furthermore, it is observed that the printed and cast samples comprise of different voids, due to the different construction processes. Finally, the results prove that the performance difference for the printed concrete at different directions possibly depends on the orientation distribution of the aggregate/fiber, as well as the irregular voids, since the aggregates/fibers are orientated by the nozzle along the printing direction.

Competitive Behavior of Isotactic Polybutene-1 Polymorphs in Electrospun Membranes and Solution Cast Films via Cold Crystallization

Isotactic polybutene-1 (iPB-1) generally crystallizes into metastable form II upon non-isothermal crystallization from the melt. The inevitable and prolonged transition of this form to form I is a drawback of numerous iPB-1 applications. In this study, electrospun (e-spun) membranes and solution cast films were prepared from the same solution, but they exhibited different crystalline behaviors. The fresh e-spun and solution cast samples contained hexagonal form I/I′ and tetragonal II, but the former was dominant in the e-spun samples. This finding was attributed to the stress-induced crystallization during electrospinning. The e-spun blend membrane of iPB-1/isotactic polypropylene (iPP) (75/25) was investigated via time-based heating-cooling protocols to obtain a stable form I′ exclusively. Upon annealing the findings revealed a distinct amount of form I′ for the e-spun blend at a quenching value of −25 °C, wherein metastable form II was suppressed entirely. The results indicate that form I′ generation in both types of samples is characterized by a confined nucleation mechanism, but in e-spun iPB-1/iPP membranes, the malleable structure favors the thermodynamics characteristics of form I′ upon heating which also reinforces the transition kinetics. The amount of form I′ was found to be directly proportional to the heating time at 185 °C, whereas it was inversely proportional to the quenching and crystallization temperatures.

Effect of alloying constituents on thermal, microstructural, mechanical and shape memory properties of Cu-Al-Ag shape memory alloys

PurposeThe purpose of this study is to assess the influence of Al and Ag addition on thermal, mechanical and shape memory properties of Cu-Al-Ag alloy.Design/methodology/approachThe material is synthesized in a controlled atmosphere to minimize the reaction of alloying elements with the atmosphere. Cast samples were homogenized, then subjected to hot rolling and further betatized, followed by step quenching. Eight samples were chosen for study among which first four samples varied in Al content, and the next set of four samples varied in Ag composition.FindingsThe testing yielded a result that the increase in binary alloying element decreased transformation temperature range but increased entropy and elastic energy values. It also improved the shape memory effect and mechanical properties (UTS and hardness). An increase in ternary alloying element increased transformation temperature range, entropy and elastic energy values. The shape memory effect and mechanical properties are enhanced by the increase in ternary alloying element. The study revealed that compositional variation of Al should be limited to a range of 8 to 14 Wt.% and Ag from 2 to 8 Wt.%. Microstructural and diffraction studies identified the ß’1 martensite as a desirable phase for enhancing shape memory properties.Originality/valueNumerous studies have been made in exploring the transformation temperature and phase formation for similar Cu-Al-Ag shape memory alloys, but their influence on shape memory effect was not extensively studied. In the present work, the influence of Al and Ag content on shape memory characteristics is carried out to increase the design choice for engineering applications of shape memory alloy. These materials exhibit mechanical and shape memory properties within operating ranges similar to other copper-based shape memory alloys.

Influence of high-intensity horizontal mould vibration on the density, grain refinement and mechanical characteristics of a die cast aluminium alloy (LM21)

The present investigation analysed the effect of mould vibration using an indigenous vibrating setup on the physical, metallurgical and mechanical properties of die cast A308 alloy. The alloy was vibrated at a constant amplitude of 31µm at 75, 100, 125 and 150 Hz. The work aims to generate more nucleation sites during melt solidification by fragmenting dendrites and Si particles. To examine the changes in metallurgical characteristics, α-Al, secondary dendritic arm spacing, length, width and aspect ratio of eutectic Si particles were studied using optical microscopy, scanning electron microscopy and X-ray diffraction analysis. It was observed that the size of α-Al, secondary dendritic arm spacing, length, width and aspect ratio of eutectic Si particles were decreased by 47%, 53%, 65%, 12% and 61%, respectively. Whereas, the shape factor and density of the alloy were enhanced by 25% and 1.62% compared to stationary cast samples because of mechanical vibration treatment at an optimum frequency of 100 Hz. Mechanical testing findings demonstrated a 13%, 20%, 15% and 20% increase in the parameters such as yield strength, ultimate tensile strength, percentage elongation and microhardness at 100 Hz when compared to the stationary cast sample. Grain refinement, uniformity of structure, improvement in the morphology of metallurgical characteristics, decreased porosities and subsequent increase in density were all factors that contributed to the improvement. Tensile test samples with scanning electron microscopy fractography demonstrated transgranular brittle fracture and a few ductile rips.

Investigation of wear and friction characteristic of Al/(Si3N4)np nano composites under as-cast and heat-treated conditions

Several automotive components, such as clutch plate, piston and cylinder liner, etc., require excellent wear characteristics. The current study focused on fabricating nano Si3N4 reinforced Al alloy composites through a stir casting route with ultrasonic assistance, then performing T-6 heat treatment to alter their properties. Dry sliding wear tests were performed to investigate the frictional and wear characteristics at various applied loads and sliding distances. Results reveal that the coarse grain of α-Al was significantly refined after incorporating nano Si3N4 particles in it, and their structure was transformed from coarse columnar to rosette-like dendrites. The hardness and wear resistance increase with nano Si3N4 addition and T-6 heat treatment. The formation of SiO2 and Fe2O3 layers at the interacting interface significantly reduces the coefficient of friction of nanocomposites. The volumetric loss increased with load (15 N to 45 N) and sliding distance (500 m to 3000 m) for cast and heat-treated samples. The maximum volumetric loss was found in the case of as-cast alloy and the minimum for heat-treated Al/2wt.% Si3N4 nanocomposites. The SEM investigation of worn surfaces shows that the adhesive mechanism is more dominant in alloys, whereas the abrasive wear mechanism was associated with nanocomposites.

Modifying Effect of a New Boron-Barium Ferroalloy on the Wear Resistance of Low-Chromium Cast Iron

This paper presents the results of a study and analysis of the effect of modifying low-chromium hypoeutectic cast iron with a new boron–barium ferroalloy on its properties—wear resistance and impact resistance—in comparison with traditional boron- and barium-containing additives. The uniqueness and novelty of the work lies in the study of the nature of changes in the structure and wear-resistant properties of low-chromium cast iron as a result of its modifying treatment with a new boron–barium ferroalloy. In a laboratory electric resistance furnace, low-chromium cast iron was melted, and four batches of prototypes were cast. Samples of the first batch, for subsequent comparison, were made without modification. When casting the remaining three batches of samples, the cast iron was modified with three different additives: ferroboron FeB12, ferrosilicobarium FeSi60Ba20, and a new complex boron–barium modifier. In order to compare the degree of effectiveness of the applied modifiers, a metallographic analysis of the structure was performed, hardness measurements were performed on the surface of the samples, and they were subjected to abrasion and cyclic shock-dynamic impact tests. In all cases, when modifying cast iron, there was an increase in hardness, a noticeable grinding of the microstructure, and a redistribution of structural components towards an increase in the proportion of perlite and finely dispersed ledeburite. A comparative analysis of the results of testing samples for dry friction and shock showed a higher surface resistance of cast samples made of modified cast iron compared to unmodified low-chromium cast iron of the same composition. A comparative study of the parameters of wear tracks and craters on damaged surfaces established that the most optimal combination of wear-resistant qualities of low-chromium cast iron occurs when it is treated with a complex boron–barium modifier, which is also evidenced by obtaining a more favorable microstructure.

Secondary dendritic arm spacing and cooling rate relationship for an ASTM F75 alloy

The solidification evolution of an ASTM F75 alloy was studied for samples quenched during directional cooling. These samples were obtained using five extraction rates (1.2–18 mm/min) and two temperature gradients (6 and 12 K/mm), leading to a 25-fold change in the cooling rate (0.13–3.31 K/s). The solidification range for this alloy is observed to be approximately 200 °C. The solid grows more rapidly in the first 100 °C of this interval, where a solid fraction of approximately 0.8–0.9 is reached. Coarsening of the Secondary Dendrite Arm Spacing, SDAS, occurs mainly during this growth period. This behavior defines an effective temperature interval for the SDAS coarsening instead of the whole solidification interval. Consideration of this effective temperature interval enables us to reconcile the measured SDAS-cooling rate relationship with that obtained from the data for the cast samples. A model of the SDAS coarsening during anisothermal solidification of multicomponent alloys is proposed. The predictions of this model compare well with the present experimental results.

Wire and Arc Additive Manufacturing of a CoCrFeMoNiV Complex Concentrated Alloy Using Metal-Cored Wire—Process, Properties, and Wear Resistance

The field of complex concentrated alloys offers a very large number of variations in alloy composition. The achievable range of properties varies greatly within these variants. The experimental determination of the properties is in many cases laborious. In this work, the possibility of using metal-cored wires to produce sufficient large samples for the determination of the properties using arc-based additive manufacturing or in detail wire and arc additive manufacturing (WAAM) is to be demonstrated by giving an example. In the example, a cored wire is used for the production of a CoCrFeNiMo alloy. In addition to the process parameters used for the additive manufacturing, the mechanical properties of the alloy produced in this way are presented and related to the properties of a cast sample with a similar chemical composition. The characterization of the resulting microstructure and wear resistance will complete this work. It will be shown that it is possible to create additively manufactured structures for a microstructure and a property determination by using metal-cored filler wires in arc-based additive manufacturing. In this case, the additively manufactured structure shows an FCC two-phased microstructure, a yield strength of 534 MPa, and a decent wear resistance.

Microstructural Evolution, Tensile Failure, Fatigue Behavior and Wear Properties of Al2O3 Reinforced Al2014 Alloy T6 Heat Treated Metal Composites.

The paper focused on an experimental study on the microstructural, mechanical, and wear characteristics of 15 wt.% alumina (Al2O3) particulates with an average particle size of 20 µm, reinforced in Al2014 alloy matrix composite as-cast and heat-treated samples. The metal matrix composite (MMC)samples were produced via a novel two-stage stir-casting technique. The fabricated composite samples were subjected to evaluate hardness, tensile strength, fatigue behavior and wear properties for both as cast and T6 heat-treated test samples. The Al2014 alloy and Al2014-15 wt.% Al2O3 MMCs were in solution for 1 h at a temperature of 525 °C, quenched instantly in cold water, and then artificially aged for 10 h at a temperature of 175 °C. SEM and X-ray diffraction analyses were used to investigate the microstructure and dispersion of the reinforced Al2O3 particles in the composite and the base alloy Al2014. The obtained results indicated that the hardness, tensile and fatigue strength and wear resistance increased when an amount of Al2O3 particles was added, compared to the as-cast Al2014 alloy and it was observed that after subjecting the same composite samples to heat treatment, there was further enhancement in the mechanical and wear properties in the Al2014 matrix alloy and Al2014-15 wt.% Al2O3 composite samples.