Improving the surface quality and mechanical properties of selective laser sintered PA2200 components by the vibratory surface finishing process

Abstract This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials. Graphic abstract

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Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽

10.3390/ma14133603 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3603

Author(s):

Tim Pasang ◽

Benny Tavlovich ◽

Omry Yannay ◽

Ben Jakson ◽

Mike Fry ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Tensile Strength ◽

Electron Beam ◽

Additive Manufacturing ◽

Selective Laser Melting ◽

Electron Beam Melting ◽

Rolling Direction ◽

Laser Melting ◽

Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

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Enhancement of Mechanical Properties and Porosity of Concrete Using Steel Slag Coarse Aggregate

Materials ◽

10.3390/ma13122865 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2865

Author(s):

Md Jihad Miah ◽

Md. Munir Hossain Patoary ◽

Suvash Chandra Paul ◽

Adewumi John Babafemi ◽

Biranchi Panda

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Microstructural Analysis ◽

Steel Slag ◽

Physical And Mechanical Properties ◽

Length Change ◽

Sustainable Building ◽

Burnt Clay ◽

Lower Porosity ◽

Furnace Steel

This paper investigates the possibility of utilizing steel slags produced in the steelmaking industry as an alternative to burnt clay brick aggregate (BA) in concrete. Within this context, physical, mechanical (i.e., compressive and splitting tensile strength), length change, and durability (porosity) tests were conducted on concrete made with nine different percentage replacements (0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100% by volume of BA) of BA by induction of furnace steel slag aggregate (SSA). In addition, the chemical composition of aggregate through X-ray fluorescence (XRF) analysis and microstructural analysis through scanning electron microscopy (SEM) of aggregates and concrete were performed. The experimental results show that the physical and mechanical properties of concrete made with SSA were significantly higher than that of concrete made with BA. The compressive and tensile strength increased by 73% when SSA fully replaced BA. The expansion of concrete made with SSA was a bit higher than the concrete made with BA. Furthermore, a significant lower porosity was observed for concrete made with SSA than BA, which decreased by 40% for 100% SSA concrete than 100% BA concrete. The relation between compressive and tensile strength with the porosity of concrete mixes are in agreement with the relationships presented in the literature. This study demonstrates that SSA can be used as a full replacement of BA, which is economical, conserves the natural aggregate, and is sustainable building material since burning brick produces a lot of CO2.

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Effects of pre-mature harvest and heat exposure on physical and mechanical properties of Pandanus tectorius leaves

10.7287/peerj.preprints.2732 ◽

2017 ◽

Author(s):

John A Toman

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Heat Exposure ◽

Physical And Mechanical Properties ◽

Maximum Growth ◽

Mechanical Efficiency ◽

French Polynesia ◽

Plant Materials ◽

Wide Range ◽

Pandanus Tectorius

Plant materials have long been utilized for human use because of their wide range of physical properties and incredible mechanical efficiency as eco-friendly structures. One example of their use today is the practice of using the sturdy leaves of Pandanus tectorius for thatching purposes. An increase in modern demand for P. tectorius is pressuring farmers to deviate from traditional harvesting methods in an attempt to increase leaf yield. With little knowledge of the repercussions of their new practice, modern farmers are pre-maturely harvesting leaves through heat-induced leaf drying while the leaves remain on the tree. In this study, life-history characteristics, physical and mechanical properties of P. tectorius leaves on Mo’orea, French Polynesia are examined to determine whether or not this deviation from traditional harvest methods reduces leaf efficacy as a thatching material. Quantitative measures of P. tectorius leaves suggest that pre-mature harvest does not alter the size of collected leaves for thatch because most leaves on a tree have already reached maximum growth. Heat-induced leaf drying, however, reduces the tensile strength of P. tectorius leaves by about 25%. Further research may find that this loss in leaf tensile strength may correlate to less robust roofing structures, hindered longevity and ultimately an increase in energy cost to repair and rebuild such structures.

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Physico-mechanical properties of cattle hide leather for working gloves with flame retardant addition

Livestock and Animal Research ◽

10.20961/lar.v18i2.42937 ◽

2020 ◽

Vol 18 (2) ◽

pp. 151

Author(s):

Iwan Fajar Pahlawan ◽

Gresy Griyanitasari

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Flame Retardant ◽

Descriptive Analysis ◽

Physical And Mechanical Properties ◽

Metal Casting ◽

Protective Equipment ◽

Elongation At Break ◽

Finishing Process ◽

Casting Industry

Objective: Indonesian metal casting industry is a labor-oriented industry which involves thermal application in the workplace. Thus, it is essential to protect the workers for any risks during their activity. Leather gloves, as personal protective equipment, need to be manufactured that can prevent the workers from burn injured. The study aimed to analyze the effect of flame retardant addition on finished leather’s physical and mechanical properties for a specific article, i.e. working gloves.Methods: The research used pickled cattle hides and commercial flame retardant as main materials. The leather chemicals used in the process are those which is commonly used to manufacture working gloves leather article. The treatments involved the addition of commercial flame retardant in fatliquoring (2%, 4%, 6% w/w) and finishing process (100 parts, 200 parts, 300 parts). The effect of flame retardant addition on shrinkage percentage, thickness, rub fastness, tensile strength, and elongation at break, were evaluated. Descriptive analysis is applied to describe the properties of the resulted finished leather.Results: The result shows that the addition of flame retardant in fatliquoring and finishing process indicates a variation in the leather’s physical-mechanical properties. The leather, manufactured with the addition of 4% (w/w) in fatliquoring, shrunk 7.65±1.42%, had tensile strength value at 520.48±13.79 kg/cm2, good rub fastness at dry and wet basis (5 and 4/5), elongation value at 52.9±4.09%, and thickness 0.87±0.02 mm.Conclusions: it can be concluded that the use of 4% (w/w) flame retardant in fatliquoring is suggested to be the best formulation to produce working gloves leather.

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CHEMICAL DEPOLYMERIZATION OF WASTE PLASTICS IN BUBBLE COLIUMN REACTOR FOR BLENDED FABRICATION

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.v21i3.564 ◽

2021 ◽

Vol 21 (3) ◽

pp. 230-239

Author(s):

Mohammed Alzuhairi ◽

Mohanad N.Alsroofy ◽

Aynoor A.Jan ◽

Waleed Bdaiwi

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Bubble Column ◽

Surface Hardness ◽

Charpy Impact ◽

Bubble Column Reactor ◽

Ftir Analysis ◽

Waste Plastics ◽

Hybrid Polymer ◽

Wide Range

The degradation of waste plastics in the environment is such an essential issue for Earth protection. This study indicated the importance of using waste bottles to produce recycled depolymerization Polyethylene Terephthalate (DPET). The bubble column reactor technique and its effect in the depolymerization process have been investigated. The DPET with Poly-methyl methacrylate (PMMA) has been used to fabricate the hybrid polymer to improve the mechanical properties. Thus, different percentages (1, 2, 3, 5, and 10 %) of (DPET) are used to surmise its repercussions on the mechanical properties of the polymer. These ramifications were studied through a sequence of research laboratory tests, including tensile strength, Charpy impact, and shore-D hardness, and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The results show a development interest, especially for impact strength and surface hardness, where both tests show compatible results, especially at (10%) of DPET. At the same time, maximum results of tensile strength are at (3%). FTIR analysis shows a chemical reaction between DPET and PMMA, which significantly improves the characteristics and makes it a wide range of available applications.

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Effect of ball burnishing medium on the surface characteristics of free machining brass

Journal of Modern Manufacturing Systems and Technology ◽

10.15282/jmmst.v4i1.3925 ◽

2020 ◽

Vol 4 (1) ◽

pp. 110-116

Author(s):

Pavana Kumara ◽

V. Vijendra Bhat ◽

G. K. Purohit

Keyword(s):

Surface Roughness ◽

Response Surface Methodology ◽

Response Surface ◽

Process Parameters ◽

Surface Hardness ◽

Surface Characteristics ◽

Surface Finishing ◽

Ball Burnishing ◽

Finishing Process ◽

Number Of Passes

Burnishing is becoming a promising surface finishing process to enhance materials surface properties. The control of the various process parameters yields the desired surface characteristics in brass materials. In the current work, free machining brass specimens were burnished by Abrasive Assisted Burnishing(AAB) process and Plain Burnishing (PB) process using ball burnishing tool. Response Surface Methodology was used to design the experiments in which Burnishing Force, Speed, Feed and Number of Passes were chosen as the process parameters. The minimum surface roughness achieved by PB and AAB was 0.1451 µm and 0.1041 µm respectively. The maximum surface hardness achieved using PB and AAB on the brass specimen was 207 HV and 248 HV respectively. The ball burnishing of free machining brass by AAB resulted in better surface characteristics as compared to the PB process.

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Characterization of physical and mechanical properties of aluminium based composites reinforced with titanium diboride particulates

Journal of Composite Materials ◽

10.1177/0021998320980800 ◽

2020 ◽

pp. 002199832098080

Author(s):

Dipankar Dey ◽

Abhijit Bhowmik ◽

Ajay Biswas

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Titanium Diboride ◽

Microstructural Analysis ◽

Physical And Mechanical Properties ◽

High Strength ◽

Casting Process ◽

Matrix Alloy ◽

Stir Casting ◽

Sem Analysis

Particulate reinforced aluminium matrix composites are one of the most attractive approaches for applications where high strength and hardness combinations are necessary. The aspiration of this study is to investigate the effect of titanium diboride addition on physical and mechanical properties of Al2024-TiB2 composites manufactured using stir casting route, by varying the weight percentages (wt.%) (0, 3, 6 and 9 percent) of titanium diboride particulates. During the casting process, stirring time and speed were kept constant and same for all the composites. Microstructural analysis demonstrates uniformity in TiB2 distribution and also strong matrix-reinforcement bonding which can be as a result of magnesium addition and preheating of titanium diboride particles before incorporating into the molten aluminium. With an increment in the wt.% of TiB2 particulates, hardness and tensile strength of the prepared composites improved, a significant improvement in hardness as well as tensile strength is encountered in Al2024-9% TiB2 composite, which is 44.94% and 35.49% higher than Al2024 matrix alloy, respectively. SEM analysis of the fractured surfaces revealed that the mode of fracture of unreinforced material is purely ductile but reinforced material fractured by nucleation of cracks and plastic deformation.

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Effects of pre-mature harvest and heat exposure on physical and mechanical properties of Pandanus tectorius leaves

10.7287/peerj.preprints.2732v1 ◽

2017 ◽

Author(s):

John A Toman

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Heat Exposure ◽

Physical And Mechanical Properties ◽

Maximum Growth ◽

Mechanical Efficiency ◽

French Polynesia ◽

Plant Materials ◽

Wide Range ◽

Pandanus Tectorius

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FIRE HAZARD AND PHYSICO-MECHANICAL PROPERTIES FOR EPOXY-AMINE COMPOSITES CONTAINING THE [Cu(DETA)(H2O)]SO4·H2O FLAME RETARDANT-HARDENER

Fire Safety ◽

10.32447/20786662.38.2021.03 ◽

2021 ◽

Vol 38 ◽

pp. 18-23

Author(s):

P. Pastuhov ◽

V. Petrovskii ◽

O. Lavrenyuk ◽

B. Mykhalitchko

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Flame Retardant ◽

Flame Propagation ◽

Fire Hazard ◽

Surface Hardness ◽

Physical And Mechanical Properties ◽

Propagation Rate ◽

Polymer Materials ◽

Epoxy Amine

Introduction. The rapid growth of production rates and the use of polymer materials in various fields has brought about an increase in the number of fires caused by the ignition of polymer products. Among the most common polymer materials are materials based on epoxy resins. They are used in such industries as construction, electrical engineering and radio engineering, shipbuilding, mechanical engineering, including automotive, aerospace and rocketry, etc. Due to its organic structure, high content of carbon and hydrogen, epoxy polymers are very combustible. Their combustion is characterized by high temperature and more flame propagation rate. And it is accompanied by significant smoke formation and the release of large amounts of toxic products. Therefore, the search for new ways to reduce combustibility and maintain the proper level of performance is one of the priorities in the development and implementation of new epoxy polymer materials in various fields. Purpose. The work aims to obtain epoxy-amine composites and to discover the effect of flame retardant-hardener on their fire hazard and physical and mechanical properties.Methods. In work used Modern research methods. The flame propagation rate was determined by UL94, the coefficient of smoke was measured by ASTM E662-19, physical and mechanical properties were evaluated by measuring parameters such as surface hardness, tensile strength, water absorption and chemical resistance.Results. The parameters of fire danger of epoxy-amine composites with different content of flame retardant (0, 5, 16 and 80 mass parts) were studied. The results of experimental studies showed that the flame propagation rate and the smoke formation coefficient in the mode of smouldering and combustion are minimal for epoxy-amine composites containing 16 and 80 mass parts of flame retardant. Such compositions have higher surface hardness and tensile strength. And they also well as more resistant to water and aggressive environments compared to unmodified ones.Conclusion. The paper presents a simple and commercially attractive method of obtaining epoxy-amine composites con-taining different amounts of flame retardant – copper(II) sulfate. It is necessary, the obtained samples of the composites are homogeneous in structure. These should be considered as individual chemicals, not as mixtures. Chemical bonding of all components of the composites, namely the appearance of additional (compared to the unmodified composite) Cu(II)–N coordination bonds in the polymer framework DGEBA/DETA-CuSO4, is reflected in the enhanced physical and mechanical properties and fire hazard reduction for this type of composite materials.

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Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

Mustansiria Dental Journal ◽

10.32828/mdj.v14i1.768 ◽

2019 ◽

Vol 14 (1) ◽

pp. 110

Author(s):

Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽

Dr. Firas Abd K. Abd K.

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Silver Nitrate ◽

Surface Hardness ◽

Mechanical Tests ◽

Hardness Tester ◽

Acrylic Resins ◽

The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

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