scholarly journals Fracture Behavior of Single-Crystal Sapphire in Different Crystal Orientations

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 930
Author(s):  
Shizhan Huang ◽  
Jiaming Lin ◽  
Ningchang Wang ◽  
Bicheng Guo ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Surface Roughness ◽  
Single Crystal ◽  
Fracture Behavior ◽  
Three Dimensional ◽  
Fracture Morphology ◽  
High Tech ◽  
Bending Tests ◽  
Three Point Bending ◽  
Single Crystal Sapphire

In order to study the anisotropy of fracture toughness and fracture mechanism of single-crystal sapphire, the three-point bending tests and the single-edge V-notch beam (SEVNB) were used to test the fracture toughness of A-plane, C-plane, and M-plane sapphire, which are widely used in the semiconductor, aerospace, and other high-tech fields. Fracture morphology was investigated by a scanning electron microscope and three-dimensional video microscopy. The fracture toughness and fracture morphology of different crystal planes of sapphire showed obvious anisotropy and were related to the loading surfaces. C-plane sapphire showed the maximal fracture toughness of 4.24 MPa·m1/2, and fracture toughness decreases in the order of C-plane, M-plane, and A-plane. The surface roughness is related to the dissipation of fracture energy. The surface roughness of the fracture surface is in the same order as C-plane > M-plane > A-plane. The fracture behavior and morphology of experiments were consistent with the theoretical analysis. C-plane sapphire cleavages along the R-plane with an angle of 57.6 degrees and the rhombohedral twin were activated. M-plane and A-plane sapphire cleavages along their cross-section.

Temperature and Orientation Dependence of Fracture Behavior of Directionally Solidified Duplex-Phase Crystals Composed of Ni3X-Type Intermetallic Compounds

2006 ◽  
Vol 512 ◽  
pp. 67-72 ◽  
Author(s):  
Koji Hagihara ◽  
Naoyuki Yokotani ◽  
Yukichi Umakoshi
Keyword(s):  
Fracture Toughness ◽  
Temperature Dependence ◽  
Lamellar Structure ◽  
Fracture Behavior ◽  
Orientation Dependence ◽  
Directionally Solidified ◽  
Bending Tests ◽  
Three Point Bending ◽  
Controlling Mechanism ◽  
Fracture Behaviors

Fracture behaviors of three directionally solidified (DS) duplex-phase alloys composed of Ni3Nb(D0a)/Ni3Al(L12), Ni6TaAl(D024)/Ni3Al(L12) and Ni3Ti(D024)/Ni3Si(L12) phases, respectively were investigated by three-point bending tests, focusing on temperature and orientation dependence. The temperature-toughness relation showed dissimilar curves depending on alloy. The increasing rate of fracture toughness was the highest in the Ni3Al/Ni3Nb alloy with fine lamellar structure and was the lowest in the Ni3Al/Ni6TaAl alloy with rod-like precipitates. The controlling mechanism for the temperature dependence of fracture behavior of Ni3Al/Ni3Nb alloys was discussed.

Anisotropic Lapping of Single Crystal Sapphire

2010 ◽  
Vol 102-104 ◽  
pp. 502-505
Author(s):  
Ping Zhou ◽  
Peng Fei Gao ◽  
Wei Fang Wang ◽  
Dong Hui Wen
Keyword(s):  
Fracture Toughness ◽  
Surface Roughness ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Orientation ◽  
Experimental Results ◽  
Single Crystal Sapphire

Lapping processes of single crystal sapphire are investigated in relation to crystallo- graphic orientation, the influence of the crystal anisotropism under different lapping liquid concentration, loading forces on materials removal rate and roughness in sapphire lapping is discussed. C-plane(0001),M-plane ( ),R-plane ( ),A-plane ( ) sapphire wafers were used for lapping experiments, experimental results show that Surface roughness is depend on the fracture toughness, surface orientation with higher fracture toughness such as C-plane would get better roughness during lapping, material removal rate of R-plane is the lowest in four planes, it is for elastic modulus and fracture toughness of R-plane are less than other three planes.

Fracture Toughness and Cracking Behaviour of SCC Compared to VC

2013 ◽  
Vol 577-578 ◽  
pp. 205-208
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter
Keyword(s):  
Fracture Toughness ◽  
Fracture Process ◽  
Critical Value ◽  
Fracture Parameter ◽  
Self Compacting Concrete ◽  
Bending Tests ◽  
Three Point Bending ◽  
Notched Specimens ◽  
Subsequent Determination

Vibrated concrete (VC) and self-compacting concrete (SCC) have a substantially different composition, resulting in dissimilar mechanical properties regarding cracking behaviour. The critical value of the mode I stress-intensity factor KICis an appropriate fracture parameter for evaluating fracture toughness and can be obtained from three-point bending tests (3PBT) on small, notched specimens. Subsequent determination of the energy release rate thus allows to examine the crack propagation and fracture process of both concrete types. This paper describes the results of such 3PBTs on samples, made from VC and SCC. Evaluation of the cracking behaviour, derived from these results, reveals remarkable differences.

Elastic modulus of single-crystal GaN nanowires

2006 ◽  
Vol 21 (11) ◽  
pp. 2882-2887 ◽  
Author(s):  
Hai Ni ◽  
Xiaodong Li ◽  
Guosheng Cheng ◽  
Robert Klie
Keyword(s):  
Elastic Modulus ◽  
Single Crystal ◽  
Vapor Deposition ◽  
Deformation Behavior ◽  
Chemical Vapor ◽  
Bending Tests ◽  
Three Point Bending ◽  
Gan Nanowires ◽  
Atomic Force ◽  
Deposition Techniques

The deformation behavior of single-crystal GaN nanowires was studied by directly performing three-point bending tests on each individual nanowire in an atomic force microscope. The elastic modulus calculated from the load–displacement response of the nanowires was 43.9 ± 2.2 GPa. Single-crystal GaN nanowires investigated in this study were synthesized by chemical vapor deposition techniques based on the vapor–liquid–solid growth mechanism and had a diameter range from 60 to 110 nm. Crystalline GaN nanowires did not show obvious plastic deformation in bending and usually failed in a brittle manner.

scholarly journals Three-Point Bending Tests of Zirconia Core/Veneer Ceramics for Dental Restorations

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Massimo Marrelli ◽  
Carmine Maletta ◽  
Francesco Inchingolo ◽  
Marco Alfano ◽  
Marco Tatullo
Keyword(s):  
Surface Roughness ◽  
Comparative Study ◽  
Mechanical Strength ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Bending Tests ◽  
Three Point Bending ◽  
Dental Restorations ◽  
Modes Of Failure ◽  
Cad Cam

Introduction. The mechanical strength and the surface hardness of commercially available yttrium-doped zirconia were investigated. Furthermore, a comparative study of eight different ceramic veneers, to be used for the production of two-layered all-ceramic restorative systems, was carried out.Materials and Methods. Four types of zirconia specimens were analyzed, according to a standard ISO procedure (ISO 6872). Besides, two-layered zirconia-veneer specimens were prepared for three-point bending tests.Results. A strong effect of the surface roughness on the mechanical strength of zirconia specimens was observed. Finally, a comparative study of eight commercially available veneering ceramics shows different modes of failure between the selected veneers.Conclusion. The results indicate that close attention should be paid to the preparation of zirconia-based crowns and bridges by CAD/CAM process, because surface roughness has an important effect on the mechanical strength of the material. Finally, the results of the mechanical tests on two-layered specimens represent an important support to the choice of the veneering ceramic.

scholarly journals 21318 Evaluation of Fracture behavior and Fracture Toughness on Single Crystal Silicon Wafers

2009 ◽  
Vol 2009.15 (0) ◽  
pp. 537-538
Author(s):  
Hiroshi NAKAMURA ◽  
Masayoshi MIYASAKA ◽  
Ryota YANAGIDA ◽  
Masayoshi TATENO
Keyword(s):  
Fracture Toughness ◽  
Single Crystal ◽  
Fracture Behavior ◽  
Single Crystal Silicon ◽  
Silicon Wafers ◽  
Crystal Silicon

scholarly journals Study on the Static and Dynamic Fracturing Properties of Marble after Being Damaged Dynamically

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yunqiu Liu ◽  
Anqi Fu ◽  
Binsong Jiang ◽  
Liyuan Yu ◽  
Xiaobing Wang
Keyword(s):  
Fracture Toughness ◽  
Impact Loading ◽  
Split Hopkinson Pressure Bar ◽  
Cumulative Damage ◽  
Bending Tests ◽  
Three Point Bending ◽  
Cyclic Impact Loading ◽  
Loading Tests ◽  
Cyclic Impact ◽  
The Impact

A split Hopkinson pressure bar (SHPB) system was first used to perform the cyclic impact loading tests on notched semicircular bend (NSCB) marble specimens. Then, static and dynamic three-point bending tests were conducted on these dynamically damaged specimens, respectively. In the cyclic impact loading tests, the dynamic elastic modulus decreases gradually as the impact number increases, but dynamic cumulative damage exhibits a growing trend. In the static and dynamic three-point bending tests, when dynamic cumulative damage is less than 0.345, the dynamic fracture toughness values are larger than the static fracture toughness values, but the experimental data exhibit the opposite results when dynamic cumulative damage ranges from 0.345 to 0.369. Through the quantitative analysis of fracture surface morphologies, the roughness and area of the fracture surfaces increase with an increasing dynamic cumulative damage. Under the same dynamic cumulative damage of the specimens, both the roughness and area of the surfaces fractured by static three-point bending are larger than those fractured by dynamic three-point bending.

scholarly journals Processing and mechanical characterization of Al2O3/Ni and Al2O3/C0 composites by pressureless sintering of nanocomposite powders

2018 ◽  
Vol 12 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Yildiz Kafkaslioğlu ◽  
Hüseyin Yilmaz ◽  
Yahya Tür
Keyword(s):  
Fracture Toughness ◽  
Metallic Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Bending Tests ◽  
Three Point Bending ◽  
Green Strength ◽  
Nanocomposite Powders ◽  
Hardness Values

Al2O3/Ni and Al2O3/Co nanopowder mixtures (with 3 vol.% of metallic phase) were synthesized by heterogeneous precipitation method. In order to increase the green strength, polypropylene carbonate (PPC) was used as a binder while preparing green compacts. Uniaxially pressed powder mixtures were sintered at 1550?C for 2 h in a reducing atmosphere. The effects of Ni and Co nanophases on the microstructure and mechanical properties of Al2O3 ceramics were studied by X-ray diffraction, scanning electron microscopy, Vickers indentation technique and three-point bending tests. The metallic phase hindered the densification of alumina matrix, yet hardness values of Al2O3, Al2O3/Ni, and Al2O3/Co composites were comparable. Vickers fracture toughness results indicate that the composites have higher fracture toughness, but the characteristic flexural strength and Weibull modulus are higher for the pure Al2O3.

Experimental investigation on Iroko wood used in shipbuilding

2016 ◽  
Vol 231 (1) ◽  
pp. 128-139 ◽  
Author(s):  
V Bucci ◽  
P Corigliano ◽  
V Crupi ◽  
G Epasto ◽  
E Guglielmino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strength Class ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Bending Tests ◽  
Three Point Bending ◽  
Test Pieces ◽  
Hardwood Species ◽  
Glued Laminated Timber ◽  
Strength And Stiffness

The paper deals with investigations about mechanical properties of Iroko, a hardwood species used for structures in shipbuilding as glued laminated timber. Experimental tests have been carried out to assess strength, stiffness and density of Iroko in accordance with current EN Standards. All the results obtained by tensile and three-point bending tests, along with the statistical analyses performed to define the characteristics values of some mechanical properties, are reported in the paper. These values allowed to assign the strength class, reported in EN 338 Standard, to the investigated Iroko wood population. The experiments have taken into account both solid timber strips and scarf-jointed strips, in order to evaluate the influence of such a type of joint, which is widely used in wooden shipbuilding on strength and stiffness. Eventually, peculiar investigations have been carried out to analyse the failure mode of some test pieces through special experimental techniques: three-dimensional computed tomography and infrared thermography.

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