Tensile strength degradation of a 2.5D-C/SiC composite under thermal cycles in air

The article presents the results of studies on the influence of simulated thermal cycles parameters on the structure and properties of the heat-affected zone (HAZ) of thermo-mechanically rolled S700MC steel. For this purpose, resistance heating tests of the tested samples were carried out to determine the effect of maximum temperatures of the imposed thermal cycles with different maximum temperatures at a constant cooling time in the temperature range between 800 and 500 °C (t8/5) and to study the influence of changes of this time on the structure and hardness as well as the tensile strength, elongation and toughness of the simulated HAZ in S700MC steel. The results of the tests, were supported by the results of finite element method (FEM) analyses in the VisualWeld (SYSWELD Code) software of the ESI Group. Selected heat distributions during heating, distributions of individual metallurgical phases and hardness were compared with results from real tests. On the basis of the results presented, an attempt was made to explain the decrease in mechanical and plastic properties in the HAZ area caused by the influence of the welding heat cycle.

Download Full-text

Fatigue characteristics of weld heat affected zone in high tensile strength steels, treated with a synthetci apparatus for weld thermal cycles (Report 2)

JOURNAL OF THE JAPAN WELDING SOCIETY ◽

10.2207/qjjws1943.37.992 ◽

1968 ◽

Vol 37 (9) ◽

pp. 992-996 ◽

Cited By ~ 1

Author(s):

Jyunjiro Muraki ◽

Takayoshi Ishiguro ◽

Hikojiro Yokota

Keyword(s):

Tensile Strength ◽

Heat Affected Zone ◽

High Tensile Strength ◽

Thermal Cycles ◽

Fatigue Characteristics ◽

Weld Heat

Download Full-text

Strength Degradation in Curved FRP bars as Concrete Reinforcement

10.20944/preprints202007.0524.v1 ◽

2020 ◽

Author(s):

Thanongsak Imjai ◽

Reyes Garcia ◽

Maurizio Guadagnini ◽

Kypros Pilakoutas

Keyword(s):

Tensile Strength ◽

Structural Damage ◽

Mechanical Performance ◽

Failure Criteria ◽

Strength Degradation ◽

Future Research ◽

Frp Composites ◽

Current Design ◽

Frp Reinforcement ◽

Superior Corrosion Resistance

Steel reinforcement in concrete has the tendency to corrode and this process can lead to structural damage. FRP reinforcement represents a viable alternative for structures exposed to aggressive environments and has many possible applications where superior corrosion resistance properties are required. The use of FRP rebars as internal reinforcements for concrete, however, is limited to specific structural elements and does not yet extend to the whole structure. The reasons for this relate to the limited availability of curved or shaped reinforcing elements on the market and their reduced structural performance. Various studies, in fact, have shown that the mechanical performance of bent portions of composite bars is reduced significantly under a multiaxial combination of stresses and that the tensile strength can be as low as 25% of the maximum tensile strength that can be developed in the straight part. In a significant number of cases, the current design recommendations for concrete structures reinforced with FRP, however, were found to overestimate the bend capacity of FRP rebar. This paper presents the state-of-the art review of the research works on the strength degradation in curved FRP composites and highlighted the performance of exiting predictive models for the bend capacity of FRP reinforcement. Recent practical predictive model based on the Tsai-Hill failure criteria by considering the material at marcromechanical level is also discussed and highlighted. The review also identifies the challenges and highlights the future directions of research to explore the use of shaped FRP composites in civil engineering applications and the trends for future research in this area.

Download Full-text

Effect of thermal cycling on mechanical and microstructural properties of heat-treated Ti-6Al-4V alloy

Materials Research Express ◽

10.1088/2053-1591/ac487d ◽

2022 ◽

Author(s):

Venkata Siva Teja Putti ◽

S Manikandan ◽

Kiran Kumar Ayyagari

Keyword(s):

Tensile Strength ◽

Ultimate Tensile Strength ◽

Weight Ratio ◽

High Strength ◽

Stress Relief ◽

Strength Properties ◽

Thermal Cycles ◽

Β Phase ◽

Solution Treated ◽

Heat Treated

Abstract Titanium (Ti-6Al-4V) is an α+β phase-field alloy utilized in many industries due to its high strength-to-weight ratio and near-net shaping capability. Solution treated & aging, and stress relief annealing processes were performed on the samples to increase the strength and % of elongation. The heat-treated samples then thermally cycled for 500 cycles, 1000 cycles, and 1500 cycles to evaluate the microhardness and tensile properties. The presence of martensite and α2 precipitates in the thermally cycled samples was confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). In this investigation, at 1000 thermal cycles, all specimens show improvement in both hardness and strength when compared within the cycles. Solution-treated and aging (STA), stress relief annealing (SRA), and without any heat-treatment (WHT) processes have their highest hardness values recorded for 1000 thermal cycles, and the values are 471 HV0.5, 381 HV0.5, and 374.6HV0.5, respectively. For the SRA process, ultimate tensile strength (UTS) of 925 MPa and yield strength (YS) of 896 MPa have resulted in 1000 cycles. Similarly, at 1000 thermal cycle WHT processed samples yielded UTS of 920 MPa and YS of 885 MPa. STA process samples that are heat-treated for 1000 thermal cycles have better strength properties than SRA and WHT and had a UTS of 1530MPa and YS of 1420MPa. From a ductility point of view, a maximum elongation of 29% for the STA process has resulted. Compared to forged titanium alloy (base metal), an increase of 31% elongation and 41% ultimate tensile strength for solution treated and aging process at 1000 cycles has resulted in this investigation.

Download Full-text

Experimental Evaluation of Strength Degradation of Orthodontic Chain Elastics Immersed in Hot Beverages

The Journal of Indian Orthodontic Society ◽

10.1177/0301574219867540 ◽

2019 ◽

Vol 53 (4) ◽

pp. 244-248 ◽

Cited By ~ 2

Author(s):

Emanuel Braga ◽

Gabriella Souza ◽

Paula Barretto ◽

Caio Ferraz ◽

Matheus Pithon

Keyword(s):

Tensile Strength ◽

Green Tea ◽

Artificial Saliva ◽

Testing Machine ◽

Strength Degradation ◽

Hot Water ◽

Group 4 ◽

Group 2 ◽

Force Reduction ◽

Elastomeric Chains

Introduction: Elastomeric chains are relevant in orthodontic mechanics due to the form memory property; however, elastomers present high force reduction in some circumstances. The objective was to evaluate the effect of hot beverages on tensile strength degradation of orthodontic elastomeric chains. Material and Methods: Four groups were tested according to different immersion liquids: artificial saliva (group 1), hot water (group 2), green tea (group 3), and coffee (group 4). The elastomeric chains of groups 2, 3, and 4 were immersed in the respective liquids, with temperature of 70 ± 1°C twice daily for 30 seconds for a period of 7, 14, or 21 days. All samples were kept in artificial saliva and stored in an incubator at controlled temperature of 37 ± 1°C. The elastomeric chains were then examined in the testing machine (AME-2kN; Filizola, São Paulo, Brazil) to measure the tensile strength degradation. Results: It was observed through intragroup comparisons that the control showed a progressive reduction of tensile strength in a statistically significant manner throughout the study period. In turn, the hot water, green tea, and coffee samples showed a statistically significant reduction from 7 to 14 days. From 14 to 21 days, the tension remained stable. When the test groups were compared with the control, it was observed that all groups presented tension reduction in a statistically significant manner at all periods, except for the coffee group at 21 days ( P < .001). Conclusions: Experimental immersion in hot water, green tea, and coffee at 70 ± 1°C contributed in a statistically significant manner to the strength degradation of orthodontic elastomeric chains in the period of 7 and 14 days.

Download Full-text

Evaluation of Substrates of Al-Mg and Aluminized Steel Coated With Non-Stick Fluoropolymers after the Removal of the Coating

Materials ◽

10.3390/ma11112309 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2309 ◽

Cited By ~ 3

Author(s):

Óscar Rodríguez-Alabanda ◽

Pablo Romero ◽

Guillermo Guerrero-Vaca

Keyword(s):

Tensile Strength ◽

Food Industry ◽

Coating Layer ◽

Protective Layer ◽

Thermal Cycles ◽

Metallic Substrates ◽

Aluminized Steel ◽

Mechanical And Microstructural Properties ◽

Steel Substrates ◽

Al Mg Alloys

Many trays and pieces of Al-Mg and aluminized steel are used in the food industry. Sometimes these elements have non-stick coatings to solve problems related to the adhesion of masses and food products. With use, the coatings deteriorate and lose efficiency and must be removed to apply a new coating. The thermal cycles suffered by these alloys during the removal process of the deteriorated coating (500 °C) and the polymerization of a new coating (400 °C) can affect the durability and efficiency of the metallic substrates. The evolution of the mechanical and microstructural properties of the Al-Mg and aluminized steel substrates after two thermal cycles was studied in this work. The following parameters were analyzed: tensile strength, elongation (%), hardness, ASTM grain size, and the nature and distribution of the constituent particles. The report concluded that the removal of the coating, after each cycle, produced a decrease in the mechanical properties of the substrates. The hardness and tensile strength in Al-Mg decreases between 20–27% and in aluminized steel between 10–11%. In both cases, the process does not compromise the reuse of the substrate for the application of a new coating layer. The final blasting stage does not affect the Al-Mg alloys but may affect the aluminized steel Al-Si protective layer if special precautions are not taken.

Download Full-text

Kinetics for the tensile strength degradation of nylon and kevlar yarns

Journal of Applied Polymer Science ◽

10.1002/app.1989.070370813 ◽

1989 ◽

Vol 37 (8) ◽

pp. 2213-2227 ◽

Cited By ~ 20

Author(s):

I. Auerbach

Keyword(s):

Tensile Strength ◽

Strength Degradation

Download Full-text

Processing of SiC-Based Fibres from Polycarbosilane

MRS Proceedings ◽

10.1557/proc-271-755 ◽

1992 ◽

Vol 271 ◽

Author(s):

Vasilios Kalyvas ◽

J. C. Ko ◽

G. C. East ◽

J. E. Mcintyre ◽

B. Rand ◽

...

Keyword(s):

Heat Treatment ◽

Tensile Strength ◽

Thermolysis Product ◽

Strength Degradation ◽

The Self ◽

Thermal Curing ◽

Oxidative Reactions ◽

High Yields

ABSTRACTA commercial polycarbosilane, thermolysis product of polysilastyrene, was spun into fibres. The self-curing character of the polymer permitted both oxidative and thermal curing of the precursor fibres. Pyrolysis of the latter produced ceramic fibres in high yields, which were fully characterised. Optimum tensile strength was attained after heat treatment at 1100°C. Oxidative reactions and crystallisation caused strength degradation above this temperature.

Download Full-text

Artificial Weathering Mechanisms of Uncoated Structural Polyethylene Terephthalate Fabrics with Focus on Tensile Strength Degradation

Materials ◽

10.3390/ma14030618 ◽

2021 ◽

Vol 14 (3) ◽

pp. 618

Author(s):

Hastia Asadi ◽

Joerg Uhlemann ◽

Natalie Stranghoener ◽

Mathias Ulbricht

Keyword(s):

Tensile Strength ◽

Polyethylene Terephthalate ◽

Building Materials ◽

Structural Changes ◽

Degradation Pathway ◽

Strength Degradation ◽

Uniaxial Tensile ◽

Accelerated Weathering ◽

Degradation Mechanisms ◽

Pet Fabric

In the past five decades, reinforced coated textile membranes have been used increasingly as building materials, which are environmentally exposed. Thus, their weathering degradation over the service life must be taken into account in design, fabrication, and construction. Regarding such structural membranes, PVC (polyvinylchloride)-coated PET (polyethylene terephthalate) fabric is one of the most common commercially available types. This paper focuses on the backbone of it, i.e., the woven PET fabric. Herein, weathering of uncoated PET, as the load-bearing component of the composite PET-PVC, was studied. This study assessed the uniaxial tensile strength degradation mechanisms of uncoated PET fabric during artificial accelerated weathering tests. For this purpose, exploratory data analysis was carried out to analyze the chemical and physical changes which were traced by Fourier transform infrared spectroscopy and molecular weight measurements. Finally, with the help of degradation mechanisms determined from the aforementioned evaluations, a degradation pathway network model was constructed. With that, the relationship between applied stress, mechanistic variables, structural changes, and performance level responses (tensile strength degradation) was assessed.

Download Full-text