Tensile Properties Of Samples Research Articles

Response surface analysis, tensile properties, and microstructure of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si fabricated by laser powder bed fusion

In this work, Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy samples under different laser process parameters were successfully fabricated by laser powder bed fusion technology. The influence of three processing parameters (laser power P, scanning speed V, and hatch spacing H) on the forming quality and tensile properties of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si samples was investigated by response surface analysis. The Non-Dominated Sorting Genetic Algorithm-II was employed to optimize and attain laser process parameters with optimal forming quality and tensile properties. Specifically, the response surface was established to reveal the optimization method of two response values (forming densification and ultimate tensile strength). The results demonstrated that hatch spacing (H) and its secondary influencing factor (H2) exerted significant effects on densification. In addition, the secondary influencing factors of laser power and hatch spacing (P2 and H2) exerted significant effects on the ultimate tensile strength of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si samples. The influence mechanism of laser process parameters on the densification and tensile properties of samples was further illuminated from the perspective of melting instability and the grain growth process. The maximum tensile strength of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si sample obtained after optimization reached above 1300 MPa. The maximum strain of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si sample with the optimal plastic performance reached 16.6%. The strength and toughness of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si samples were analyzed from the aspects of the microstructure and phase composition.

Laser beam weldability of TiZrHfNbTa high entropy alloy and dissimilar weldability to C103 refractory alloy

Weldability is one of the most important processes for new metallic alloys moving toward engineering applications. In this work, both the laser beam weldability of an equiatomic TiZrHfNbTa refractory high entropy alloy (HEA) and the dissimilar weldability of TiZrHfNbTa to C103 niobium-based alloy are assessed. Single BCC phase maintains stability around both the TiZrHfNbTa welding joint and HEA-C103 dissimilar welding joint. Fine equiaxed grains are obtained within these two types of weld fusion zones with no detectable macro- or microcracks formation. Despite the existence of a small amount of porosity in the fusion zone, the tensile properties of samples containing welding joints are comparable to the corresponding base materials. This work confirms the prototype TiZrHfNbTa refractory HEA has excellent laser weldability and meanwhile exhibits good dissimilar weldability to widely used C103 alloy.

Comparison of wear and mechanical properties of cast and 3D printed CuSn10 bronze alloy

Abstract This paper aims to provide a comparison between properties of CuSn10 bronze alloy produced by two methods: FDM (fused deposition modelling) and casting. Wear behavior, mechanical performance and microstructure of CuSn10 alloy produced by FDM and casting methods were determined and compared. 3D printed parts were sintered at 875 °C for 5 h and casting was done at 1200 °C. The amount of porosity was determined by the metallographic cross-sectional examination. Vicker’s hardness, wear and tensile properties of samples were determined. As a result, the porosity value of the CuSn10 alloy produced by the FDM technique was determined as 5.07 ± 0.53%. Tensile strength values were 233.75 ± 18.48 MPa and 349.04 ± 5.10 MPa for CuSn10 alloys produced by FDM and casting methods respectively. While adhesive wear occurs in both production methods, it was observed that the FDM method reduced the wear resistance.

Effect of wire composition on microstructure and properties of wire and arc additive manufactured ZAlCu5MnCdVA aluminum alloy

PurposeWire and arc additive manufacturing (WAAM) technology-based cold metal transfer (CMT) to produce large aluminum alloy parts has become more and more popular. In WAAM, wire is the only raw material. The purpose of this paper is to study the effect of wire composition on the microstructure and properties of the ZAlCu5MnCdVA alloy deposited by WAAM.Design/methodology/approachTwo thin-walled ZAlCu5MnCdVA alloys with different wire compositions were prepared by WAAM. The copper contents were 4.7% (Al-4.7Cu) and 5.0% (Al-5.0Cu), respectively. The microstructure, element distribution and evolution of precipitated phases of the two samples were characterized and analyzed by optical microscopy, scanning electron microscopy and transmission electron microscopy. Hardness and tensile properties of samples were tested, and strengthening mechanism was analyzed in detail.FindingsThe results show that grain sizes of Al-4.7Cu and Al-5.0Cu are less than 40 μm. The average mass fraction of Cu in Al matrix and the number of nanometer scale θ'' and θ' phases are the main factors affecting the tensile properties of Al-Cu alloy. Tensile properties of two materials show different characteristics at room temperature and high temperature. Al-5.0Cu is better at room temperature and Al-4.7Cu is better at high temperature. The yield strength (YS), ultimate tensile strength (UTS) and elongation in the x direction of Al-5.0Cu at room temperature are 451 ± 10.2 MPa, 486 ± 10.2 MPa and 9 ± 0.5%, respectively. The YS, UTS and elongation in the x direction of Al-4.7Cu at high temperature are 290 ± 4.5 MPa, 356 ± 7.0 MPa and 13% ± 0.2%, respectively.Originality/valueExperiments show that the increase of Cu element can improve the properties at room temperature of the ZAlCu5MnCdVA alloy by WAAM, but its properties at high temperature decrease.

Heterogeneous microstructure and anisotropic mechanical properties of reduced activation ferritic/martensitic steel fabricated by wire arc additive manufacturing

• Reduced activation ferritic/martensitic steel was fabricated by wire arc additive manufacturing. • The as-deposited microstructure exhibited the heterogeneous band characteristics. • Microstructure differences caused the periodical hardness and anisotropic tensile properties. • A potentially detrimental softening zone, was found at the heat-affected zone of the as-deposited RAFM steel. Reduced activation ferritic/martensitic (RAFM) steel is an iron-based alloy as a candidate structural material in fusion reactor. This paper evaluates the compatibility of RAFM steel as a choice material for wire arc additive manufacturing (WAAM). Two specimens of RAFM steels with high and low heat input were fabricated by WAAM. The effects of the heat input on the microstructure, microhardness and tensile properties of samples were investigated. The fusion boundaries are spaced uniformly in the whole sample. Three distinctive zones were present in the periodic region, including heat-affected zone (HAZ), columnar grains zone and fine-grained zone occurred alternatively. The HAZ was affected by the heat input. The fully γ-annealed top region consisted of epitaxial elongated grains without HAZ. The periodic pattern in microhardness along the building direction was found which was related to the periodic microstructure featured. The tensile properties presented anisotropic characteristics due to the heterogeneous microstructure. Further analysis indicated that the grain coarsening in the HAZ and C precipitates distributed at the grain boundaries caused substantial softened in the HAZ, resulted in the lower localized microhardness and tensile strength. Compared to the high heat input specimen, the low heat input specimen had smaller grain sizes, higher microhardness and tensile properties.

Batch production and fused filament fabrication of highly aligned discontinuous fibre thermoplastic filaments

Fused filament fabrication (FFF), which is a thermoplastic layer-by-layer additive manufacturing technique, called as 3D printing, can quickly build complex geometries, reducing design limitations and production costs of conventional manufacturing methods. Using a fibrous reinforcement strengthens the thermoplastic matrix, allowing FFF to be used in more structural complex-shape small-size applications in engineering. Aligned discontinuous fibre composites (ADFRC) incorporate a high-performance reinforcement architecture that, owing to a sufficient fibre length and high level of alignment, results in mechanical performance comparable to those of continuous fibre composites. Moreover, it can offer higher formability and, fewer manufacturing defects. In this paper, ADFRC preforms, produced with the High Performance Discontinuous Fibre (HiPerDiF) technology, were impregnated with poly(L-lactic acid) (PLA) and then reshaped to a circular-shaped 3D printing filament using a customised manual moulding and pultrusion method. Two different mould types were compared to maximise the filament quality and reduce the amount of trapped voids. The printability of the circular filaments was investigated by varying three parameters: deposition speed, processing temperature, and layer thickness. Finally, the tensile properties of samples from each manufacturing step: moulded, filament, single raster printed, and full height rectangular part, were investigated. Overall, the HiPerDiF-PLA filament can be printed using an 3D printer. Although the tensile properties of filament in each stage reduced as the result of the shape transformation process, the deposited layer of HiPerDiF-PLA part has greater stiffness and strength than other PLA composite materials. At this stage of technology development, the material has lower mechanical performance yet than the nylon continuous fibre composites printed with commercially available machines. However, there are clear routes forward for the improved performance of the HiPerDiF FFF printed filaments.

Impact of laser scanning speed on microstructure and mechanical properties of Inconel 718 alloys by selective laser melting

Inconel 718 alloys were fabricated by selective laser melting under different scanning speeds to investigate the change of the morphology of molten pool, direction of grain growth, and tensile properties. Results show that as the scanning speed increases from 1,000 to 1,450 mm·s−1, the ratio between depth and width of molten pool increases, yet their overlapping regimes decrease. Meanwhile, increasing scanning speed can promote the solidified structure evolve from cell to columnar dendrites, and decrease the dendrite spacing from 0.54 to 0.39 µm; the average columnar grain size also decreases from 84.42 to 73.51 µm. At different scanning speeds, the preferred orientation of grains along the building is mainly <001> direction. In addition, the tensile properties of samples under different scanning speeds present a non-monotonic transition. The maximum ultimate tensile strength and elongation can reach 1,014±19 MPa and 19.04±1.12 (%), respectively, at the scanning speed of 1,300 mm·s−1.

Directed Energy Deposition of PA12 carbon nanotube composite powder using a fiber laser

Directed Energy Deposition (DED) an AM-technology that is widely known for its applications with metals was adapted for use with thermoplastics. A drop-in approach was used based on a DED setup for metal powders consisting of a Yb fiber laser with a wavelength of 1075 nm and a powder feed from a coaxial powder nozzle. The possibility of manufacturing items with simple geometries from a polyamide 12 multi-walled carbon nanotube composite starting material is described as a proof of concept. Tensile properties of samples are reported for measurements perpendicular and parallel to the generating direction, showing still a low strength compared to Bulk PA12 or SLS sintered PA12 specimens.

Microstructures and tensile properties of CuZrAlNb metallic glass composites under different cooling rates

AbstractCu48-xZr48Al4Nbx (x = 1 or 5 at.%) metallic glass composite rods with diameters of 4 mm, 3 mm and 2 mm were prepared by using copper mold drop-casting. Their microstructures and tensile properties under different cooling rates were investigated. The microstructure and tensile properties of samples were affected by the crystalline phase content. With the increase in Nb content or the decrease of cooling rates, the microstructures of samples crystallized more significantly and the tensile fracture strength reduced. The fracture mode changed from shear fracture to brittle fracture, shear bands on the side surface decreased and vein stripes on the fracture surface were transformed into plastic pit structures as Nb content increased from 1 to 5%. The results may be helpful for the investigation of metallic glass composite mechanical behavior.

Tensile and Morphological Properties of Microcellular Polymeric Nanocomposite Foams Reinforced with Multi-walled Carbon Nanotubes

Polyamide 6 (PA6) is used in many applications due to its advantages and improving its properties seems essential. For this purpose in the present study, PA6 was melt compounded with various multi-walled carbon nanotubes (MWCNTs) contents and then was foamed using Azodi carbon amide (ACA) as blowing agent under different injection molding conditions. Morphological properties were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests. The results demonstrated that an appropriate distribution of MWCNTs was observed in polymeric matrix and 0.85, 0.94 and 1 A increase in distance between walls of CNTs was observed. Also, the SEM results illustrated that microcellular structure was achieved in all samples. The results illuminated that mean cell size was improved about 34% in samples containing 1 wt% MWCNT. The tensile properties of samples were investigated and the effect of MWCNTs content was studied on specific tensile and yield strengths. The results indicated that specific tensile strength and yield strength were significantly increased almost 164% and 147% by addition of 1 wt% of MWCNTs, respectively.

Processing and tensile properties of A356 composites containing in situ small-sized Al3Ti particulates

This research proposed an in situ casting method for preparing Al3Tip/A356 composites with high strength and good ductility by adding Ti powders into molten A356 at 800°C. A sampling experiment was firstly carried out to explore the evolution process of Ti powders in the A356 melt. Based on which in situ Al3Tip/A356 composites with 1.5 and 3.0wt% Ti additions were fabricated respectively. Both the microstructures and tensile properties of samples after T6 heat treatment were investigated. The results showed that blocky Si-substituted Al3Ti particulates were synthesized in the in situ reaction and the formation of which followed a reaction-peeling model. The utilization ratio of Ti powders in the fabricating process could research 70%. In situ Al3Ti particulates existed inside the α-Al crystals of A356 alloy, with the size smaller than 10µm. Both the equiaxed transition from long columnar dendrite structure and refining of α-Al crystals occurred due to the nucleating effect of Al3Ti. Compared with T6-A356, the yield strength, ultimate tensile strength, and percent elongation of the T6-A356/3.0Ti were improved by 29.2%, 36.0% and 143.6%, respectively. The mechanisms of the improved tensile properties, including the strength and ductility, of the composites were also discussed in this research.

Effects of Oxygen Content on Tensile and Fatigue Performance of Ti-6Al-4 V Manufactured by Selective Laser Melting

We investigated the selective laser melting (SLM) process for development of Ti-6Al-4 V solid material with oxygen content corresponding to the extra low interstitial (ELI) and non-ELI conditions. The microstructure, chemistry, and tensile properties of samples in as-built and hot isostatically pressed (HIPed) condition were evaluated for both material types, while fatigue performance was evaluated by rotating bending fatigue tests on both smooth and notched SLM ELI and non-ELI Ti-6Al-4 V samples in HIPed condition.

Structure and properties of ethylene/propylene copolymers synthesized with bis(2,4,7-trimethylindenyl)zirconium dichloride activated by methyl aluminoxanes containing different amount of trimethylaluminum

Ethylene/propylene copolymerization was catalyzed under the same conditions with unbridged metallocene bis(2,4,7-trimethylindenyl)zirconium dichloride (Cat.1) activated by aluminoxane type cocatalysts having different content of trimethylaluminum (TMA). Chain structure of the copolymers was characterized by 13C NMR and thermal analysis on copolymer fractions separated based on crystallinity. Changing the cocatalyst from commercial methylaluminoxane (MAO, containing both free TMA and bond TMA) to dried MAO (dMAO, containing only bond TMA) and BHT-treated MAO (BMAO, containing almost no TMA) caused only slight differences in polymerization activity and moderate increase in copolymer molecular weight, but marked differences in copolymer chain structure. The copolymers produced using MAO (sample 1) and dMAO (sample 2) as cocatalysts contain high amount of fractions with very low propylene content and almost isolated propylene units. The copolymer produced using BMAO as cocatalyst (sample 3) has very broad composition distribution, but its fraction with the highest crystallinity has much higher content of PP dyads than the crystalline fractions of the other two samples. This sample has the lowest crystallinity among the three samples. Phase morphology and tensile properties of the copolymer changed markedly when different cocatalyst was used. Tensile properties of sample 1 and 2 were similar to mixtures of elastomer and crystalline plastic materials, but tensile properties of sample 3 were more or less like a thermoplastic elastomer. Influences of TMA on the micro scale environment of active centers were considered the main reason for the effects of cocatalyst on copolymer structure and properties.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Die-Cast AZ91D Alloy with RE Elements

The effect of online solution and subsequent age heat treatment on microstructure and mechanical properties of die-cast AZ91D +1wt. %RE alloy were researched. The results indicated that online solution heat treatment led to inhibit some β-Mg17Al12 phase precipitation, and remained the Al element in matrix plays a role of solid solution strengthening. The online solution samples were aged at 160°C, 180°Cand 200°C. Microstructure results suggested that age treatment caused some lamellar β-Mg17Al12 phases precipitated near grain boundaries. The tensile properties of samples under air cool, online solution and subsequent age heat treatment were tested, which UTS were 194 MPa, 243 MPa and 244 MPa, and the elongation were 3.67%, 3.97% and 1.6%, respectively. The results indicated that the online solution could enhance the mechanical properties significantly, which the subsequent age heat treatment could not improve.

Influence of surface layer on properties of hipped Ti–6Al–4V

The nature of the surface region formed between Ti–6Al–4V and the mild steel tooling used to define the shape of net shape hot isostatically pressed (hipped) Ti–6Al–4V components has been evaluated. The surface topography has been assessed and analytical scanning electron microscopy (SEM) has been used to define the local changes in composition obtained under several hipping conditions. The tensile and fatigue properties of net shape hipped samples of Ti–6Al–4V have been compared with those obtained from samples produced by machining samples from larger hipped cylinders so that the surface layer is removed. The as hipped surface is irregular on the scale of the original powder particles and a 150 μm thick diffusion layer is produced under the standard hipping conditions. It has been found that the tensile properties of samples with the as hipped or machined surfaces are very similar. The fatigue limits of samples which were tested with the as hipped surface were significantly below those of samples which were machined to remove the as hipped surface. Electropolishing the as hipped samples to a depth of ∼150 μm leads to fatigue properties which are slightly higher than the properties of machined samples. These results are discussed in terms of the failure mechanisms during fatigue and issues in the production of net shape hipped products.

Tensile and Compressive Properties of the Medial Rabbit Meniscus

Quantification of the material properties of the meniscus is of paramount importance, creating a 'gold-standard' reference for future tissue engineering research. The purpose of this study was to determine the compressive and circumferential tensile properties in the rabbit meniscus. Creep and recovery indentation experiments were performed on the meniscus using a creep indentation apparatus and analysed via a finite element optimization method to determine the compressive material properties at six topographical locations. Tensile properties of samples taken circumferentially from the rabbit meniscus were also examined. Results show that the femoral side of the anterior portion exhibits the highest aggregate modulus (510 +/- 100 kPa) and shear modulus (240 +/- 40 kPa), while the lowest aggregate modulus (120 +/- 30 kPa) and shear modulus (60 +/- 20 kPa) were found on the femoral side of the posterior location. Values of 156.6 +/- 48.9 MPa for Young's modulus and of 21.6 +/- 7.0 MPa for the ultimate tensile strength of were found from the tensile samples, which are similar to the values found in other animal models. These baseline values of material properties will be of help in future tissue engineering efforts.

Advances in optimisation of mechanical properties in cast TiAl alloys

The room temperature tensile properties of a number of cast TiAl-based alloys, which have been grain-refined either by additions of boron or by a new quenching and ageing treatment, have been assessed. It has been found that in the alloys which have been grain-refined by boron addition, the size of the titanium boride particles, which is strongly influenced by the size of the cast samples, is an important factor in limiting the tensile ductility. The tensile properties of samples which have been quenched and aged can be significantly improved and it has been shown that this grain refinement technique, which is based on the massive transformation, can be applied to a wide range of alloys. Quenching to above the ductile-to-brittle temperature, but below the temperature at which the massive transformation occurs, reduces the tendency for cracking during this type of heat treatment. The potential for producing cast components using these two approaches to grain-refinement is discussed.

Influence of impurities on mechanical properties of recycled glass fiber reinforced polyamide 66

AbstractThis work investigates the influences of impurities on the durability and the reliability of the mechanical properties of recycled glass fiber reinforced polyamide 66. A critical size‐concentration zone could be determined based on changes in tensile properties of samples containing untreated glass beads of different size and concentrations, which were used as simulated impurities in in‐plant reprocessed material. Characterization of samples based on recyclate from post‐use radiator end‐caps, which contained residues of EPDM rubber, showed that the tensile strength was almost unaffected by rubber particles up to an equivalent diameter, d, of ∼700 μm. However, a significant strength reduction commenced for rubber particles larger than 1200–1300 μm, and the strength showed a correlation with d−1/2. Furthermore, large simulated impurities (425–590 μm) in in‐plant material and rubber residues in post‐use recyclate showed a negative effect on the mechanical reliability.