The microstructure and mechanical properties of Co/YCF102 composite coating

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenchao Xi ◽  
Boxue Song ◽  
Jinlong Dong ◽  
Tianqi Zhang ◽  
Tianbiao Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Composite Coating ◽  
Laser Cladding ◽  
Machine Tools ◽  
Base Material ◽  
Mixed Powder ◽  
Content Type ◽  
High Microhardness ◽  
Aisi 1045

Purpose Laser cladding has been used in the field of repairing damaged parts of machine tools due to its advantages of less processing restrictions and easy formation of a good metallurgical bond with the base material. However, the mechanical properties of the coating sometimes cannot meet the process requirements. Therefore, the purpose of this paper is to prepare coatings with high microhardness and flexural strength. Design/methodology/approach The YCF102 alloy powder was mixed with different contents of Co and tested for laser cladding on AISI 1045 substrate under the same process parameters. The main phase composition of the coating was revealed by the XRD results. The main chemical composition of the coating was determined by the SEM and EDS results. In addition, the effect of Co content on the microstructure, microhardness and flexural strength of the coatings was investigated. Findings The results show that when the Co content is 2 wt% and 4 wt%, Co does not form compounds with other elements, but is uniformly distributed in the coating. And when the Co content is 6 wt% and 8 wt%, the Co reacts with Fe in the coating and generates Co3Fe7 in situ. The increase in Co did not result in a monotonic change in microhardness, but significantly improved the flexural strength and the flatness of the microstructure of the coating. When the Co content of the mixed powder is 8 wt%, the coating has high microhardness and flexural strength. Originality/value Co/YCF102 composite coating with high microhardness and flexural strength was prepared. This paper provides a theoretical and practical basis for research in the area of repairing damaged parts of machine tools by laser cladding.

Effect of using magnetic water on the mechanical properties of concrete exposed to elevated temperature

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wasim Barham ◽  
Ammar AL-Maabreh ◽  
Omar Latayfeh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Flexural Strength ◽  
Tap Water ◽  
Splitting Tensile Strength ◽  
Content Type ◽  
Normal Water ◽  
Magnetic Water

PurposeThe influence of using magnetic water instead of tap water in the mechanical properties of the concrete exposed to elevated temperatures was investigated. Two concrete mixes were used and cast with the same ingredients. Tap water was used in the first mix and magnetic water was used in the second mix. A total of 48 specimens were cast and divided as follows: 16 cylinders for the concrete compressive strength test (8 samples for each mix), 16 cylinders for the splitting tensile strength (8 specimens for each mix) and 16 beams to test the influences of magnetized water on the flexural strength of concrete (8 specimens for each mixture). Specimens were exposed to temperatures of (25 °C, 200 °C, 400 °C and 600 °C). The experimental results showed that magnetic water highly affected the mechanical properties of concrete. Specimens cast and curried out with magnetic water show higher compressive strength, splitting tensile strength and flexural strength compared to normal water specimens at all temperatures. The relative strength range between the two types of water used was 110–123% for compressive strength and 110–133% for splitting strength. For the center point loading test, the relative flexural strength range was 118–140%. The use of magnetic water in mixing concrete contribute to a more complete hydration process.Design/methodology/approachExperimental study was carried out on two concrete mixes to investigate the effect of magnetic water. Mix#1 used normal water as the mixing water, and Mix#2 used magnetic water instead of normal water. After 28 days, all the samples were taken out of the tank and left to dry for seven days, then they were divided into different groups. Each group was exposed to a different temperature where it was placed in a large oven for two hours. Three different tests were carried out on the samples, these tests were concrete compressive strength, flexural strength and splitting tensile strength.FindingsExposure of concrete to high temperatures had a significant influence on concrete mechanical properties. Specimens prepared using magnetic water showed higher compressive strength at all temperature levels. The use of magnetic water in casting and curing concrete can increase the compressive strength by 23%. Specimens prepared using magnetic water show higher splitting tensile strength at all temperatures up to 33%. The use of magnetic water in casting and curing can strengthen and increase concrete resistance to high temperatures, a significant enhancement in flexural strength at all temperatures was found with a value up to 40%.Originality/valuePrevious research proved the advantages of using magnetic water for improving the mechanical properties of concrete under normal conditions. The potential of using magnetic water in the concrete industry in the future requires conducting extensive research to study the behavior of magnetized concrete under severe conditions to which concrete structures may be subjected to. These days, there are attempts to obtain stronger concrete with high resistance to harsh environmental conditions without adding new costly ingredients to its main mixture. No research has been carried out to investigate the effect of magnetic water on the mechanical properties of concrete exposed to elevated temperature. The main objective of this study is to evaluate the effect of using magnetic water on the mechanical properties of hardened concrete subjected to elevated temperature.

Effect of layer thickness on irreversible thermal expansion and interlayer strength in fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 943-953 ◽  
Author(s):  
Anthony A. D’Amico ◽  
Analise Debaie ◽  
Amy M. Peterson
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Layer Thickness ◽  
Fused Deposition Modeling ◽  
Thermal Strain ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
The Impact

Purpose The aim of this paper is to examine the impact of layer thickness on irreversible thermal expansion, residual stress and mechanical properties of additively manufactured parts. Design/methodology/approach Samples were printed at several layer thicknesses, and their irreversible thermal expansion, tensile strength and flexural strength were determined. Findings Irreversible thermal strain increases with decreasing layer thickness, up to 22 per cent strain. Tensile and flexural strengths exhibited a peak at a layer thickness of 200 μm although the maximum was not statistically significant at a 95 per cent confidence interval. Tensile strength was 54 to 97 per cent of reported values for injection molded acrylonitrile butadiene styrene (ABS) and 29 to 73 per cent of those reported for bulk ABS. Flexural strength was 18 to 41 per cent of reported flexural strength for bulk ABS. Practical implications The large irreversible thermal strain exhibited that corresponding residual stresses could lead to failure of additively manufactured parts over time. Additionally, the observed irreversible thermal strains could enable thermally responsive shape in additively manufactured parts. Variation in mechanical properties with layer thickness will also affect manufactured parts. Originality/value Tailorable irreversible thermal strain of this magnitude has not been previously reported for additively manufactured parts. This strain occurs in parts made with both high-end and consumer grade fused deposition modeling machines. Additionally, the impact of layer thickness on tensile and flexural properties of additively manufactured parts has received limited attention in the literature.

Effects of welding speeds on the microstructural and mechanical properties of AZ91D Mg alloy by friction stir welding

2020 ◽  
Vol 11 (6) ◽  
pp. 769-782 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Base Material ◽  
Welding Parameters ◽  
Content Type ◽  
Friction Stir ◽  
Az91d Magnesium Alloy ◽  
Transverse Tensile

PurposeThe main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.Design/methodology/approachMicrostructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.FindingsMetallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.Research limitations/implicationsIn the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.Practical implicationsMagnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.Originality/valueLimited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

Preparation of Porous Titanium Dental Implant by 3D Printing/Composite Coating and Its Biomechanical Properties and Flexural Strength

2020 ◽  
Vol 12 (10) ◽  
pp. 1492-1501
Author(s):  
Chengxue Yang ◽  
Zhengwen Yu ◽  
Yuanzhu Long ◽  
Lin Chen
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Flexural Strength ◽  
Dental Implants ◽  
Composite Coating ◽  
Test Specimen ◽  
Biomechanical Properties ◽  
Porous Titanium ◽  
Nano Coating ◽  
Flexural Resistance

Dental implants have been widely used in clinical practice. The 3D modeling software was used to design threedimensional (3D) models (in the shapes of long strips, discs, and screws), i.e., the Ti2.6Al1.2 V0.42 specimens. Meanwhile, the implant material was electrochemically precipitated, and a layer of chitosan nano-coating was added to the surface. To test the bone-binding ability and planting success rate of the material, the mechanical properties of the specimens with different porosity (0%∼70%) were firstly analyzed by the three-point bending method. Then, the screw-shaped titanium alloy specimens were divided into the solid group, the solid coating group, the solid 30% group, the coating 30% group, the solid 50% group, and the coating 50% group. The MC3T3-E1 cells were cultured, and the in vitro biological properties of the specimens were tested from different angles. The biomechanical properties and flexural strength of screw-shaped titanium alloy specimens in different groups were tested by using a universal testing machine. In the experiment, the prepared dental implants had the complete surface, uniform pore distribution, dense coating distribution, and less overall cracks. The elastic gradient of porous titanium specimens would decrease due to the increase of porosity. The cell activity of the test specimen was higher, and the percentage of viable cells exceeded 80%. The MTT test confirmed that the pores of the test specimen could promote the increase of MTT value (P < 0.05), and the test specimen/composite coating had higher ALP levels compared with the test pieces with no surface treatments (P < 0.05). In biomechanical properties and flexural strength tests, the increase of pores increased the biomechanical properties (P < 0.05) and decreased the flexural resistance (P < 0.05), while the increase of coating decreased the biomechanical properties and increased the flexural resistance (P < 0.05). The porous titanium alloy specimens were successfully prepared, and the chitosan-based composite coating was applied. The material was non-toxic, which was beneficial to cell proliferation and had good mechanical properties, thereby contributing to the growth of new bone.

Evaluation of the mechanical properties of WC-FeAl composite coating fabricated by laser cladding method

2020 ◽  
Vol 88 ◽  
pp. 105199 ◽  
Author(s):  
Alireza Mostajeran ◽  
Reza Shoja-Razavi ◽  
Morteza Hadi ◽  
Mohammad Erfanmanesh ◽  
Masoud Barekat ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Coating ◽  
Laser Cladding

Research on Microstructure and Hardness of Laser Cladding Using the Mixed Powder of Nano-TiC and Ni-Based Alloy

2020 ◽  
Vol 976 ◽  
pp. 9-14 ◽  
Author(s):  
Wei Zhang ◽  
Qiu Hong Feng ◽  
Wei Zhong Zhang
Keyword(s):  
Solid Solution ◽  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
High Speed ◽  
Scanning Speed ◽  
Mixed Powder ◽  
Reinforced Composite ◽  
Average Hardness ◽  
Cladding Material

Aiming at the problem of poor high-temperature wear-resistance of rope clamp used in super-high speed elevators, the experiments of laser cladding to prepare carbide reinforced composite coating were made. nanoTiC powder, Ni-based alloy powder were used as cladding material. The microstructure and hardness of composite coating were tested by relevant equipments. The research results show that the composite coating is made up of TiC, Cr3C2, Fe3C and Fe-Ni-Cr-C HYPERLINK "javascript:void (0);" solid solution. When the content of TiC is 10%, 30%, the morphology of TiC is presented as dendrite-like and the morphology of HYPERLINK "javascript:void (0);" solid solution is presented as cellular-like. When the content of TiC is 50%, the morphology of TiC is presented as block-like, lath-like. There are some microcracks on grain boundaries. At the content of 30%, laser power 1.5KW, scanning speed 600mm/min, the laser cladding has no crack and hole. The average hardness of composite coating is 701HV0.2. Using this technology to the surface strengthening of elevator parts, the wear resistance and service life can be greatly improved.

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