Investigation on Mechanical Properties of 6H-SiC Crystal

2013 ◽  
Vol 423-426 ◽  
pp. 251-257
Author(s):  
Min Jin ◽  
Jia Yue Xu ◽  
Yao Qing Chu ◽  
Yong Zheng Fang ◽  
Hui Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Applied Load ◽  
Vickers Microhardness ◽  
Brittleness Index ◽  
Microindentation Technique ◽  
Indenter Penetration

In this work, the mechanical properties, such as Vickers microhardnessHv, fracture toughnessKc, yield strengthσvand brittleness indexBi, of <0001> oriented 6H-SiC crystal are systematically evaluated using a microindentation technique under 0.1-2 kg applied load. It is found theHvis decreased as the applied load is increased which is mainly attributed to the effect of indenter penetration. TheHvvalue can be effectively presumed by Kicks law and the Meyers indexnis determined to be 1.73. However, theKcvalue is measured nearly a constant (~0.148 MPa.m1/2) which reveals the toughness of 6H-SiC(0001)crystal is much weaker than those of Si(100)and GaAs(100)crystals. The variation ofσvto the load is similar to that ofHv. The brittleness indexBialso exhibits deceasing tendency as the applied load is added.

scholarly journals Влияние содержания корунда и температуры спекания на механические свойства керамических композитов CaO-ZrO-=SUB=-2-=/SUB=--Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

2018 ◽  
Vol 44 (4) ◽  
pp. 25 ◽  
Author(s):  
А.А. Дмитриевский ◽  
А.И. Тюрин ◽  
А.О. Жигачев ◽  
Д.Г. Гусева ◽  
П.Н Овчинников
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Mechanical Characteristics ◽  
Vickers Microhardness ◽  
Ceramic Composites ◽  
Optimum Regime ◽  
Two Stage

AbstractWe have studied the mechanical properties (Vickers microhardness H _V and fracture toughness K _C) of nanostructured CaO–ZrO_2–Al_2O_3 ceramic composites as dependent on the content of corundum (0 ≤ $$C_{Al_{2}O_{3}}$$ C A l 2 O 3 ≤ 25%) and the temperature of sintering (1250°C ≤ T _1 ≤ 1500°C). Optimum value of the corundum content ( $$C_{Al_{2}O_{3}}$$ C A l 2 O 3 = 5%) and optimum regime ( T _1 = 1300°C, 5 min; T _2 = 1200°C, 4 h) of two-stage sintering are established, which favor attaining the best mechanical characteristics of ceramic composites ( H _V = 12.25 GPa, K _C = 8.47 MPa m^1/2).

Mechanical Properties of a Medium Carbon Low Alloy Steel Processed by Two Step Austempering Process

2010 ◽  
Vol 638-642 ◽  
pp. 3453-3458 ◽  
Author(s):  
Susil K. Putatunda ◽  
Abhijit Deokar ◽  
Gowtham Bingi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Alloy Steel ◽  
High Yield ◽  
Bainitic Steel ◽  
Low Alloy Steel ◽  
High Yield Strength ◽  
Medium Carbon

A new bainitic steel with a combination of exceptionally high yield strength and fracture toughness has been developed. This steel has been synthesized by austempering a medium carbon low alloy steel by a novel two-step austempering process. The influence of this two-step austempering on the microstructure and the mechanical properties of this new steel have been examined.

CARLSON ALLOY NITRONIC 40

Alloy Digest ◽  
2015 ◽  
Vol 64 (10) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Yield Strength ◽  
Magnetic Permeability ◽  
Cold Working ◽  
Heat Treating ◽  
Ambient Temperatures ◽  
Temperature Performance

Abstract Carlson Alloy Nitronic 40 has corrosion resistance superior to 316L and 317L with twice the yield strength at ambient temperatures. Possesses good mechanical properties at both elevated and sub-zero temperatures. Retains low magnetic permeability even after severe cold working or at sub-zero temperatures. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1228. Producer or source: G.O. Carlson Inc..

Integrating Automated Ball Indentation With ASME B31G Code to Assess Integrity of Corroded Pipelines

2004 ◽  
Author(s):  
Fahmy M. Haggag ◽  
Larry D. Phillips
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Maximum Depth ◽  
Operating Pressure ◽  
Test Technique ◽  
Efficient Operation ◽  
Ball Indentation ◽  
Corrosion Pits ◽  
Safe Operating

In order to provide deterministic structural integrity assessment for safe and efficient operation of corroded pipelines, the following information is required: (a) the actual key mechanical properties (yield and ultimate strength, and fracture toughness) of the pipeline materials, (b) the present thickness and diameter of the pipeline, and (c) the profile of the maximum depth of corrosion pits over the pipeline axial length, and the size of sharp cracks. Both items (b) & (c) can be determined by conventional techniques. A patented in-situ Stress-Strain Microprobe (SSM) system was used to provide item (a), the required key mechanical properties (tensile and fracture toughness), in a nondestructive and localized fashion without any interruption of the pipeline transmission using its novel Automated Ball Indentation (ABI) test technique. The SSM system was used on a short segment of a 356-mm (14-inch) diameter Kerosene pipeline. Although there was no documentation of the pipeline steel grade, the minimum ABI-measured yield strength at four locations was 277 MPa (40.2 ksi) and the minimum ultimate tensile strength was 378 MPa (54.8 ksi) indicating that the steel met the requirements of Grade “A”. Both the Rstreng software and the ASME B31G code were used to calculate the maximum safe operating pressure for the corroded pipeline. The calculations showed that a profile with a few corrosion pits [3–6 mm (0.075–0.236 inch) maximum depth spaced over 483 mm (19 inches) length] reduced the maximum safe pressure significantly from 4.24 MPa (615 psi) to 0.74 MPa (107 psi). The operator of the pipeline limited the maximum operating pressure to 0.69 MPa (100 psi). Furthermore, it was recommended that the ABI measurements be performed on at least 10% of the 7-km Kerosene pipeline and on all patches and welds in order to provide the minimum yield strength values required for determining the remaining strength of the pipeline. This work proves that the integration of the ABI measurements with the corrosion pitting profile allows calculation of the maximum safe operating pressure in order to make the appropriate decision of replacement or repair of certain pipeline sections.

A Study on the Nondestructive Evaluation of Material Degradation

2006 ◽  
Vol 326-328 ◽  
pp. 685-688
Author(s):  
Hyung Ick Kim ◽  
Yong Huh ◽  
Jeong Pyo Kim ◽  
Chang Sung Seok
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Nondestructive Evaluation ◽  
Evaluation System ◽  
Ultrasonic Method ◽  
Indentation Test ◽  
Experimental Results ◽  
Material Degradation ◽  
Ultrasonic Parameters

The mechanical properties of in-service facilities under harsh environment a decrease as materials of the facilities degrade. This decrease of mechanical properties can affect the safety operation of the facilities. Therefore, the extent of degradation due to prolonged service exposure must be estimated. Nondestructive evaluation method is a good technique for monitoring the change of mechanical properties of in-service facilities. The most widely used nondestructive methods are the ultrasonic method and the indentation test, which is advantageous with respect of applicability to in-service facilities. The modified theoretical Vary's equation, considering nonlinear response due to material degradation, was proposed for obtaining the correlations between ultrasonic parameters and fracture toughness. Experimental results showed that ultrasonic attenuation, velocity, and nonlinear parameters have significant correlation with fracture toughness and yield strength. The nondestructive evaluation system can be used to obtain the yield strength and ultrasonic parameters simultaneously, and this information can be used to predict the fracture toughness. The predicted results produced good correlations with the experimental results, indicating that the nondestructive evaluation system can be effective in evaluating material properties and degradation, and the life time of facilities.

Effect of Cerium and Lanthanum Addition on Mechanical Properties of Bismuth Titanate Ceramics

2009 ◽  
Vol 409 ◽  
pp. 330-333
Author(s):  
Nina Pavlovic ◽  
Dragan Rajnovic ◽  
L. Sidjanin ◽  
Vladimir V. Srdic
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Bismuth Titanate ◽  
Vickers Microhardness ◽  
Grain Morphology ◽  
Sintering Behaviour ◽  
Titanate Ceramics ◽  
Hardness Values ◽  
Microhardness Tester

Cerium- and lanthanum- substituted bismuth titanate (Bi4-xAxTi3O12; where A=La or Ce, and x=0, 0.5 and 1) ceramics were prepared from nanopowders synthesized by coprecipitation method. The as-synthesized powders were calcined, uniaxially pressed and finally sintered at 1050°C. It was shown that sintering behaviour, phase composition and grain morphology of the obtained ceramics were influenced by the presence of lanthanum and especially cerium ions in the titanate structure. Mechanical properties (hardness and fracture toughness) were measured at room temperature on polished sample surfaces using a Vickers microhardness tester. The hardness values for of bismuth titanate based ceramics were in the range for some other important perovskite titanate, whereas their fracture toughness was somewhat higher.

DILLIMAX 1100

Alloy Digest ◽  
2012 ◽  
Vol 61 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Fine Grained ◽  
Minimum Yield

Abstract Dillimax 1100 is a high-strength, quenched and tempered, fine-grained structural steel with minimum yield strength of 1100 MPa (160 ksi). Its mechanical properties are achieved by water quenching followed by tempering. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-663. Producer or source: Dillinger Hütte GTS.

Efffect of Spark Plasma Sintering Temperature on Mechanical Properties of In Situ TiB/Ti Composites

2014 ◽  
Vol 881-883 ◽  
pp. 923-926
Author(s):  
Xiang Bo Shen ◽  
Zhao Hui Zhang ◽  
Mao Sheng Cao ◽  
Fu Chi Wang
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Spark Plasma Sintering ◽  
Vickers Microhardness ◽  
Sintering Temperature ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Plasma Sintering ◽  
Spark Plasma

The in-situ synthesized TiB reinforced titanium matrix composites have been prepared by spark plasma sintering technique at 950–1250°C, using mixtures of 10wt% TiB2 and 90wt% Ti powders. The effects of the sintering temperature on the mechanical properties (Vickers microhardness, yield strength and Young`s modulus) of the composites were investigated. SEM was used to analyze the reaction process and the microstructure of the compacts synthesized at different sintering temperatures. The results indicated that the in situ synthesized TiB grow rapidly with increasing sintering temperature. The composite sintered at 1250°C have the highest relative density of 99.2%. However, the composite sintered at 950°C exhibits the best Vickers microhardness of 4.64GPa and yield strength of 989MPa, respectively.

scholarly journals The effect of lanthanum addition on the microstructure and mechanical properties of Mg-modified hydroxyapatite ceramics

2021 ◽  
Vol 15 (3) ◽  
pp. 226-237
Author(s):  
Serdar Pazarlioglu ◽  
Ogulcan Algan ◽  
Mert Isikogullari ◽  
Hasan Gokce
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Tricalcium Phosphate ◽  
Biomedical Application ◽  
Brittleness Index ◽  
Beta Tricalcium Phosphate ◽  
Hydroxyapatite Ceramics ◽  
Superior Mechanical Properties ◽  
Increasing Temperature

In the present paper, the effect of La2O3 (0.25, 0.5 and 1 wt.%) addition on the phase stability, porosity, density, hardness, fracture toughness, compressive strength and brittleness index of hydroxyapatite modified with 1 wt.% of MgO was investigated. Hydroxyapatite (HA) without additives sintered at 1300?C has mixture of dominant hydroxyapatite phase with beta-tricalcium phosphate (?-TCP), alpha-tricalcium phosphate (?-TCP) and calcium oxide (CaO) phases. The microstructure is characterized with transgranular microcracks and oversized grains. Although the density and hardness of the pure HA increased with increasing temperature, a steady decrease in fracture toughness (from 0.96 to 0.71MPa?m1/2) and compressive strength (from 130.2 to 65.6MPa) was observed. For the HA modified with 1 wt.% of MgO the highest compressive strength (183.2MPa) and fracture toughness (1.47MPa?m1/2) were obtained at 1200?C and at this temperature the brittleness index was 3.24 ?m-1/2. Increase in the sintering temperature led to the increase of the brittleness index of the pure HA,MgO modified HA and La2O3-MgO modified HA samples. The addition of 1 wt.%La2O3 to 1 wt.% MgO-HA contributed to the increase in the compressive strength of about 10%(from 183.2 to 202.0MPa), fracture toughness of about 69% (from 1.37 to 2.32MPa?m1/2) and also decrease of the brittleness index from 3.24 to 2.18 ?m-1/2. The best performance after sintering at 1300?C was obtained for the MgO-HA sample with 0.25wt.% La2O3. As a result of this study, a new candidate material for biomedical application with superior mechanical properties and the phases that do not cause adverse reactions in the human body could be 1 wt.% MgO-HA modified with 1 wt.% La2O3 and sintered at 1200?C.

Mechanical Properties and Synthesis of Nanocrystalline Ta – 1.67Al2O3 Composite by Pulsed Current Activated Heating

2021 ◽  
Vol 21 (7) ◽  
pp. 4042-4045
Author(s):  
Na-Ra Park ◽  
In-Jin Shon
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Applied Load ◽  
Synthesis Method ◽  
High Energy ◽  
Pulsed Current ◽  
Grain Sizes ◽  
Milling Method ◽  
Energy Ball ◽  
Short Time

Mixtures of Ta2O5 and Al nanopowders were prepared using high energy ball milling method. Nanocrystalline Ta – 1.67Al2O3 composite was simultaneously synthesized and densified by pulsed current activated combustion synthesis method in a short time from mechanically activated mixtures of Ta2O5 and Al powders. The relative density of the Ta – 1.67Al2O3 composites was 98%. The average grain sizes of Ta and Al2O3 in the Ta – 1.67Al2O3 composite heated up to 1520 °C were determined as 205 and 40 nm, respectively. A Vickers diamond indentation technique were used to evaluate the hardness and fracture toughness of the Ta – 1.67Al2O3 composite under applied load 20kgf. The average Vickers hardness and fracture toughness value were 1340 kg/mm2 and 7.9 MPa·m1/2, respectively.

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