Evaluation of the brittleness and viscosity of metals upon tensile testing

2021 ◽  
Vol 87 (3) ◽  
pp. 51-57
Author(s):  
Yu. V. Bugrov ◽  
A. A. Hlybov ◽  
M. K. Chegurov
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Tensile Testing ◽  
Testing Machine ◽  
Residual Austenite ◽  
Stiffness Index ◽  
Before And After ◽  
Temperature Dependences ◽  
Correlation Decrease ◽  
Treatment Procedures

The indicators of the brittleness and viscosity of metals calculated from their mechanical properties are considered with allowance for the stress state proceeding from the results of tensile testing of cylindrical smooth and notched samples of perlite 16KhSN, martensitic-aging (maraging) 03Kh11N10M2T, and austenitic 10Kh11N23T3MR steels. Tests were carried out on a UEM-10TM tensile strength testing machine, deformation diagrams developed on a scale of ~50:1 at a deformation rate of 5 mm/min. The sample size before and after testing were measured using a micrometer and an ISA-2 comparator with an accuracy of ±10–3 mm. Pendulum impact bending tests were carried out on a MK15 with the same cylindrical notched samples used to plot the plasticity and viscosity diagrams depending on the Bridgman stress state stiffness index. The new indicators of the brittleness λ = εk/η and viscosity η = (Sk/σb) – 1 (where εk = ln(1/(1 – ψk)) is the true limit plasticity) are proposed proceeding from the testing data. The special feature of the brittleness index λ is growth of the index with increase in the metal strength, e.g., due to pre-deformation or strengthening heat treatment procedures. However, a decrease in the groove radius on the samples, i.e., an increase in the Bridgman stress state stiffness, has almost no effect on the brittleness value λ, but is accompanied by a correlation decrease in the values of the viscosity indices η and the ultimate ductility εk of steels. The curves of the temperature dependences of the mechanical properties of steels 16KhSN and 03Kh11N10M2T show that anomalies in the brittleness indices λ observed at elevated test temperatures can be attributed to the structural transformations like increase in the grain size of 16KhSN steel or in the amount of the residual austenite in 03Kh11N10M2T steel due to reverse martensitic transformation. In this case, the temperature dependences of the viscosity η and brittleness λindicators change in the opposite way.

scholarly journals Effect of Er on Microstructure and Mechanical Properties of 5052 Aluminum Alloy with Big Width-To-Thickness Ratio

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 568
Author(s):  
Xinwei She ◽  
Xianquan Jiang ◽  
Bao Qi ◽  
Kang Chen
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
Testing Machine ◽  
Thickness Ratio ◽  
Tensile Testing Machine ◽  
Microstructure And Mechanical Properties ◽  
Long Time ◽  
Scanning Electron ◽  
Al Matrix

The effect of Er on microstructure and mechanical properties of the 5052 aluminum alloy with a big width-to-thickness ratio was investigated by a metallurgical microscope, scanning electron microscope and tensile testing machine. The results showed that the precipitates were slightly refined after Er addition and Al3Fe was transformed into Al6Fe and AlEr with/without a small amount of Fe or Si. The effect of Er on grain refinement was related to its content. When Er content was lower or higher than 0.4%, the grain would coarsen. Homogenization could refine the grain by controlling Er content and distribution in the Al matrix. Long time homogenization at high temperature would significantly reduce the strength of the 5052 aluminum alloy and 5052 aluminum alloys with low Er content, but help to improve the plasticity of those with high Er content. The ultimate tensile strength, yield strength and elongation of the as-cast 5052 aluminum alloy were 197 MPa, 117 MPa and 22.5% respectively. The strength was the highest, when Er content was 0.4 wt. % and the elongation was the best at 0.1 wt. % Er content.

Influence of plastic deformation temperature on the structure and mechanical properties of low-alloy copper alloys with Co, Ni and B

2017 ◽  
Vol 84 (2) ◽  
pp. 49-57 ◽  
Author(s):  
B. Grzegorczyk ◽  
W. Ozgowicz
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Strain Rate ◽  
Minimum Temperature ◽  
Deformation Temperature ◽  
Tensile Testing ◽  
Copper Alloys ◽  
Testing Machine ◽  
Temperature Range ◽  
Ductility Minimum

Purpose: This work presents the influence of chemical composition and plastic deformation temperature of CuCoNi and CuCoNiB as well as CuCo2 and CuCo2B alloys on the structure, mechanical properties and, especially on the inter-crystalline brittleness phenomenon and ductility minimum temperature effect in tensile testing with strain rate of 1.2·10-3 s-1 in the range from 20°C to 800°C. Design/methodology/approach: The tensile test of the investigated copper alloys was realized in the temperature range of 20-800°C with a strain rate of 1.2·10-3 s–1 on the universal testing machine. Metallographic observations of the structure were carried out on a light microscope and the fractographic investigation of fracture on an electron scanning microscope. Findings: Low-alloy copper alloys such as CuCo2 and CuCo2B as well as CuCoNi and CuCoNiB show a phenomenon of minimum plasticity at tensile testing in plastic deforming temperature respectively from 500°C to 700°C for CuCo2, from 450°C to 600°C for CuCo2B and from 450°C to 600°C for CuCo2B and from 500°C to 600°C for CuCoNiB. Practical implications: In result of tensile tests of copper alloys it has been found that the ductility minimum temperature of the alloys equals to about 500°C. At the temperature of stretching of about 450°C the investigated copper alloys show maximum strength values. Originality/value: Based on the test results the temperature range for decreased plasticity of CuCoNi and CuCoNiB as well as CuCo2 and CuCo2B alloys was specified. This brittleness is a result of decreasing plasticity in a determined range of temperatures of deforming called the ductility minimum temperature.

Mechanical Properties of Winding Conductors Affected by Cyclic Thermal Overloads

2006 ◽  
Vol 113 ◽  
pp. 541-544 ◽  
Author(s):  
N. Višniakov ◽  
J. Novickij ◽  
D. Ščekaturovienė ◽  
M. Šukšta
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix ◽  
Room Temperature ◽  
Pure Copper ◽  
Testing Machine ◽  
Liquid Nitrogen Temperature ◽  
Ultimate Tensile Stress ◽  
Climatic Chamber ◽  
Fast Heating ◽  
Before And After

The influence of thermal cyclic overloads on mechanical properties of winding conductors was investigated. Copper-niobium microcomposite, soft and hard pure copper wires were conditioned at temperatures range from 77 K to 500 K. The treatment was done during 100 cycles of fast conductor cooling to liquid nitrogen temperature and further fast heating in a climatic chamber. The ultimate tensile stress limit and the elongation at failure of metal-matrix copper-niobium microcomposite, soft and hard copper wires were measured before and after thermal treatment with a testing machine at room temperature.

Microstructure and Mechanical Properties of Mg-9Gd-4Y-0.5Zr Alloy

2017 ◽  
Vol 904 ◽  
pp. 15-18
Author(s):  
Bo Bo Meng ◽  
Quan An Li ◽  
Xiao Ya Chen
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Tensile Testing ◽  
Treatment Process ◽  
Testing Machine ◽  
Elongation Rate ◽  
Heat Treatment Process ◽  
Tensile Testing Machine ◽  
Microstructure And Mechanical Properties

The effects of heat treatment on microstructure and mechanical properties of Mg-9Gd-4Y-0.5Zr alloy were studied by XRD, OM, SEM and tensile testing machine. The results show that the alloy mainly consists of α-Mg matrix, Mg5Gd and Mg24Y5. Through solid solution and aging heat treatment process, the tensile strength, yield strength and elongation rate respectively achieves 263.1MPa, 235.2MPa and 3.11%.

Elasto-Plastic Properties of Thin Gold Films Over Polymeric Substrates

2008 ◽  
Author(s):  
F. Avile´s ◽  
L. Llanes ◽  
A. I. Oliva ◽  
J. E. Corona ◽  
M. Aguilar-Vega ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Tensile Testing ◽  
Testing Machine ◽  
Ultimate Strain ◽  
Film Deposition ◽  
Thickness Effect ◽  
Gold Films ◽  
Polymeric Substrates ◽  
Film Substrate

Metallic thin films have been extensively used as coatings, interconnections, sensors and as part of micro and nano-electromechanical devices (MEMS and NEMS). The conventional substrates utilized to deposit those films are normally rigid, such as silicon. However, for applications where the substrate is subjected to significant mechanical strain (e.g. automotive coatings, electronic textiles, bioengineering, etc.) the film-substrate system needs to be flexible and conformable. Compliant polymeric substrates are ideal candidates for such a task. Some interesting mechanical properties not achieved with conventional rigid substrates can be transmitted to the film by the use of polymeric substrates. In this work, mechanical properties of 50 to 300 nm gold films deposited by thermal deposition over two thermoplastic substrates are investigated. A commercial thermoplastic, Polysulfone (“PSF”), and a home-synthesized isophthalic polyester based on the reaction of 4, 4′-(1-hydroxyphenylidene) phenol and isophthaloyl dichloride (“BAP”) [1] were used as raw materials for substrate production. Substrates were selected based on their good mechanical properties and flexibility. The use of two different substrates allows us to investigate the influence of the substrate mechanical properties in the bimaterial response. Substrates of 80 μm thickness were prepared by solution casting and cut to rectangular shapes of nominal dimensions of 30 mm × 5 mm. High purity (99.999%) commercial gold splatters were used for film deposition. Gold films with thickness of 50, 100, 200, and 300 nm were deposited onto PSF substrates by thermal evaporation inside a vacuum chamber at 3×10−5 Torr. Au films with 100 nm thickness were also deposited over BAP substrates. Four replicates of each type were deposited (at the same time) and used for tensile testing. Tensile testing of Au/PSF (film thickness 50–300 nm) and Au/BAP (film thickness 100 nm) specimens was conducted. Tests of the neat PSF and BAP substrates (6 replicates) were also conducted as a baseline. Tensile testing was conducted in a small universal testing machine with a load cell of 200 N and a cross head speed of 0.05 mm/min. The film mechanical properties were extracted from the tensile response of the film/substrate system, considered as a bimaterial. Based on sum of forces and strain compatibility, the film modulus (Ef) and stress (σf) can be extracted from characteristics of the bimaterial (EBim, σBim) and substrate (Es, σs), to generate a stress-strain curve for the film, see e.g. [2], Ef=1Af[ABimEBim−AsEs]=1+tstfEBim−tstfEs(1a)σf=1Af[P−Ps]=1+tstfσBim−tstfσs(1b) where P is the applied load, A = wt is the cross sectional area and sub-index “Bim” corresponds to the film-substrate bimaterial (ABim = w(ts+tf)). Figure 1 shows film stress (σ)-strain (ε) representative curves for Au films with different thicknesses extracted from the Au/PSF bimaterials. The film behavior presents only a small region of plasticity close to the ultimate strain. Thus, the numerical value of the maximum stress (strength) is close to its yield strength. The large plasticity of the substrate may hinder the plasticity of gold when acting as a bimaterial. As observed from this figure, the film modulus, strength and ultimate strain increase as the film thickness decreases, evidencing a “thickness-effect” not observed in bulk materials. Slightly different properties were obtained for the Au films deposited over the BAP substrate, which evidences some substrate-dependency of the film properties.

Effect of Coarse-Grained Ring on Mechanical Properties and Cutting Performance of 2011 Aluminum Alloy Extruded Bar

2021 ◽  
Vol 1035 ◽  
pp. 114-118
Author(s):  
Chang Liang Shi ◽  
Yan Ping Niu ◽  
Yi Min Lin ◽  
Quan Hu ◽  
Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Eutectic Phase ◽  
Cutting Performance ◽  
Coarse Grained ◽  
Tensile Testing Machine

The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al7Cu2Fe phase, CuAl2 phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.

Effect of the Stretch Rate During Uniaxial Testing on the Mechanical Properties of Prolene®

2012 ◽  
Author(s):  
T. M. Bazi ◽  
A. H. Ammouri ◽  
R. F. Hamade
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Relative Elongation ◽  
Testing Machine ◽  
Peak Load ◽  
Displacement Rate ◽  
Uniaxial Tensile ◽  
P Value ◽  
Stretch Rate ◽  
Uniaxial Tensile Testing

We assess the effects of stretch rate on the mechanical properties of Prolene® (Ethicon, Gynecare, Somerville, NJ, USA), a knitted polypropylene mesh. Prolene®, consisting of macroporous knitted polypropylene, is considered here as a suitable proxy to midurethral tape (MUT) as well as to many other prosthesis products used in surgery applications. Such products are utilized to treat urine incontinence, pelvic organ prolapse, as well as hernia in humans. Of the mechanical properties of special significance are the following three properties: peak load (N), extension (%) at peak load, and linear stiffness (N/mm). Uniaxial tensile testing was performed on mesh samples on a universal testing machine and involved loading different samples at 5 cross-head speeds of: 1, 10, 50, 100, and 500 mm/min. The corresponding properties were measured under these 5 conditions. In order to minimize damage to the specimens at the jaws, special dual action pneumatically operated grips with rubber faced jaws were used to hold the samples in place. The effectiveness of these grips was illustrated by the fact that none of the failed samples broke at grips. Statistically significant findings suggest an increasing trend for Prolene® stiffness vs. stretch rate (R2 = 0.9679; two-tailed p value = 0.0025) where the stiffness increases 26.2% when increasing the displacement rate from 1 to 500 mm/min. For extension (%) at peak load, a decreasing trend was found vs. stretch rate (R2 = 0.81; two-tailed p value = 0.037) where increasing the displacement rate from 1 mm/min to 500 mm/min corresponds to a 22% decrease in the relative elongation of the mesh. No statistically significant dependence of peak load on stretch rate was found. These findings may help workers in the biomedical field develop suitable uniaxial tensile testing protocols of such materials.

scholarly journals Investigation of the fluids influence on change of sandstones collectors mechanical properties during saturation and degassing

2019 ◽  
Vol 109 ◽  
pp. 00103
Author(s):  
Serhii Tynyna ◽  
Vasyl Babenko
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Mechanical Characteristics ◽  
Partial Discharge ◽  
Laboratory Studies ◽  
Deformation Properties ◽  
Before And After ◽  
Surface Active ◽  
Sandstone Formation ◽  
State Of The Environment

The article discusses the effect of fluids on the properties of rocks. It is known that surface active environments, including gas, can significantly change the mechanical characteristics of solids. To establish the dependence of the effect of methane on the strength characteristics of rocks, the results of full-scale and laboratory studies are considered. The experiments were carried out on samples of outburst sandstone formation m3, taken at a depth of 915 m. Analysis of research results allowed to establish the effect of changes in gas saturation of rocks on their mechanical properties before and after degassing and partial discharge of experimental areas after they have been worked by lavas along m3 formation. It has been established that the reason for the increase in drillability and strength of sandstones was their degassing, and not a change in the stress state of the environment. This led to a change in the deformation properties of rocks in gas-saturated and degassed states.

scholarly journals Effects of Carbonated Drinks on Mechanical Properties of Three Types of Thermoplastic Aligner Materials: An In vitro Study

2020 ◽  
Vol 54 (2) ◽  
pp. 115-120
Author(s):  
Leyona Pushpa Femina I. ◽  
Chandrashekar B.S. ◽  
Arun A.V ◽  
Aravind S. Raju ◽  
Ramesh Kumar P.C. ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Artificial Saliva ◽  
Testing Machine ◽  
In Vitro Study ◽  
Control Groups ◽  
Universal Testing ◽  
In Vitro Aging ◽  
Before And After ◽  
Carbonated Drinks

Objectives: The aim was to assess the mechanical properties of the three types of thermoplastic aligner materials before and after in vitro aging with carbonated drinks. Materials and methods: Twelve samples of thermoplastic aligner materials produced by three different manufacturers (Leone S.P.A, Florence, Italy; Duran, SCHEU-dental GmbH, Iserlohn, Germany; Essix ACE, Dentsply Raintree Essix, United States) were selected. Samples were thermoformed and later aged in vitro at a constant temperature in artificial saliva along with carbonated drinks (10 min each day) for 2 weeks. The mechanical properties were characterized using universal testing machine such as instron (MultiTest 10-i) and the results were compared with the control groups (before exposure to carbonated drinks). Results: All the above-mentioned thermoplastic materials tested showed an insignificant ( p > 0.05) decrease in stiffness, yield strength, and elastic modulus after aging. The stiffness of the thermoplastic materials increased with an increase in thickness. The flexure modulus was higher for the thinner materials, whereas it was lower for the thicker materials. Conclusion: Experimental results indicate that the aligner material will remain stable during and following exposure to carbonated drinks, which suggests that the orthodontic force from thermoplastic appliances does not decrease with clinical usage of carbonated drinks.

Effect of B Refinement on Structure and Fracture Morphology of Al-7 wt.% Si Alloy

2014 ◽  
Vol 590 ◽  
pp. 181-186
Author(s):  
Xiao Song Li ◽  
An Hui Cai ◽  
Ji Jie Zeng
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Testing ◽  
Testing Machine ◽  
Fracture Morphology ◽  
Optical Microscope ◽  
Tensile Testing Machine ◽  
Alloy Microstructure ◽  
Scanning Electron

Using optical microscope, electronic tensile testing machine, scanning electron microscopy methods, such as detailed treatment of the B hypoeutectic Al-Si alloy microstructure, mechanical properties and fracture morphology were studied. The results showed that after treatment by the B refinement, α-Al dendrite phase was refined, resulting in mechanical properties of Al-Si alloy significantly improved. Which, B content 0.036wt.%, the alloy the best, the σb, δ, respectively, than the non-thinning increased 67.8% and 15.2%. From the fracture surface, the fracture morphology of the specimen showed a quasi-cleavage fracture. Which, B content 0.036wt.% at the time of fracture is more deep dimples, and a good plastic toughness.

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