Pressureless Sintering and Properties of Cu/Ti3AlC2 Composites

2008 ◽  
Vol 368-372 ◽  
pp. 998-1000 ◽  
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Ming Xing Ai ◽  
Yi Wang ◽  
Hong Bing Zhang
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Vickers Hardness ◽  
Layered Structure ◽  
Volume Content ◽  
Al Alloy ◽  
Pressureless Sintering ◽  
Copper Powders ◽  
Interface Bond

The Cu/Ti3AlC2 composites were fabricated by pressureless sintering a mixture of Ti3AlC2 and copper powders. Their microstructures and properties were investigated. It was found that the molten Cu accelerating the decomposition of Ti3AlC2, inducing the interfacial exfoliation to generate, and forming a sub-micro-layered structure making up of TiCx layers and Cu-Al alloy layers within a Ti3AlC2 grain. The flexural strength of the composites is reduced with the increase of the volume content of Ti3AlC2 from 50 % to 90 %. The highest flexural strength reaches to as high as 915 MPa. The fracture mode was changed from ductile to brittle with increase in the content of Ti3AlC2. The higher flexural strength can be attributed to a stronger interface bond between TiCx and Cu-Al phase. The electrical resistivity and Vickers hardness of the composites were also measured.

Unusual Microstructures and Strength Characteristics of Cu/Ti3AlC2 Cermets

2007 ◽  
Vol 336-338 ◽  
pp. 1394-1396 ◽  
Author(s):  
Hong Xiang Zhai ◽  
Ming Xing Ai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
...  
Keyword(s):  
Fracture Strength ◽  
Volume Content ◽  
Deformation Rate ◽  
Strength Characteristics ◽  
Al Alloy ◽  
Fracture Face ◽  
Three Point Bending ◽  
Copper Powders ◽  
Network Feature ◽  
Interface Bond

Cu/Ti3AlC2 cermets prepared by pressless sintering a mixture of Ti3AlC2 and copper powders were investigated. It was found that the Cu/Ti3AlC2 possesses an unusual microstructure made up of sub-micro-sheet layered Ti3C2 and Cu-Al alloy within one Ti3AlC2 particulate. The fracture strength measured by the three-point-bending manner is increased but the deformation rate is reduced with increase in the volume content of Ti3AlC2 from 30 % to 90 %. The highest fracture strength reached to as higher as 983.9 MPa, corresponding to an extreme strain of 2.64 %. The fracture in mode was changed from brittle to ductile with reduce in the content of Ti3AlC2. The higher fracture strength can be attributed to a stronger interface bond between Ti3AlC2 and Cu-Al phase. A significant network feature formed by the Cu-Al alloy surrounding Ti3AlC2 particulates was observed from the fracture face.

Properties of B4C-Based Composite with Layered Structure

2014 ◽  
Vol 602-603 ◽  
pp. 532-535
Author(s):  
Zhen Nan Li ◽  
Si Yang Fan ◽  
Xin Yan Yue ◽  
Zhao Bin Sun ◽  
Jian Jun Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Layered Structure ◽  
Hot Pressing ◽  
Interfacial Bonding ◽  
Bearing Surface ◽  
Load Bearing ◽  
Porous Preform ◽  
Layer Composite

A three-layer material based on B4C/Al, B4C/TiB2 and B4C composites had been successfully prepared. The microstructures and properties of B4C/Al-B4C/TiB2-B4C composite were investigated in detail. The three-layer porous preform was first prepared by hot pressing. Then the three-layer composite was fabricated by infiltrating aluminum into the porous preform in vacuum. The three-layer B4C/Al-B4C/TiB2-B4C composite showed good interfacial bonding. When using the B4C ceramics layer as the load-bearing surface, the flexural strength, fracture toughness and Vickers hardness of the composite were 230 MPa, 3.4 MPa·m1/2 and 38 GPa, respectively.

scholarly journals Synthesis, microstructure, and properties of high purity Mo2TiAlC2 ceramics fabricated by spark plasma sintering

2020 ◽  
Vol 9 (6) ◽  
pp. 759-768
Author(s):  
Yunhui Niu ◽  
Shuai Fu ◽  
Kuibao Zhang ◽  
Bo Dai ◽  
Haibin Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Layered Structure ◽  
High Purity ◽  
High Fracture Toughness ◽  
Temperature Range ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractThe synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase was formed from the reaction among Mo3Al2C, Mo2C, TiC, and C. Dense Mo2TiAlC2 bulk sample was prepared by spark plasma sintering (SPS) at 1673 K under a pressure of 40 MPa. The relative density of the dense sample was 98.3%. The mean grain size was 3.5 μm in length and 1.5 μm in width. The typical layered structure could be clearly observed. The electrical conductivity of Mo2TiAlC2 ceramic measured at the temperature range of 2–300 K decreased from 0.95 × 106 to 0.77 × 106 Ω–1·m–1. Thermal conductivity measured at the temperature range of 300–1273 K decreased from 8.0 to 6.4 W·(m·K)–1. The thermal expansion coefficient (TEC) of Mo2TiAlC2 measured at the temperature of 350–1100 K was calculated as 9.0 × 10–6 K–1. Additionally, the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa, high flexural strength of 407.9 MPa, high fracture toughness of 6.5 MPa·m1/2, and high compressive strength of 1079 MPa. Even at the indentation load of 300 N, the residual flexural strength could hold 84% of the value of undamaged one, indicating remarkable damage tolerance. Furthermore, it was confirmed that Mo2TiAlC2 ceramic had a good oxidation resistance below 1200 K in the air.

Online-Joining of C/SiC-C/SiC via Slurry Reaction and Precursor Infiltration and Pyrolysis Process with C/SiC Pins

2012 ◽  
Vol 531-532 ◽  
pp. 135-140 ◽  
Author(s):  
Yu Di Zhang ◽  
Hai Feng Hu ◽  
Chang Rui Zhang ◽  
Guang De Li
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Pyrolysis Process ◽  
Strong Bond ◽  
Sic Composites ◽  
Maximum Shear Strength ◽  
Application Prospects ◽  
Complex Components

C/SiC composites have widely application prospects in the field of aeronautic and aerospace for their excellent properties. The joining of C/SiC composites is a key to fabricate large and complex components. In this paper, 1D C/SiC pins were prepared by precursor infiltration and pyrolysis (PIP) process and used to join C/SiC composites by Slurry react (SR) and PIP process. The shear strength of the C/SiC pins with different carbon fiber volumes was investigated with the maximum shear strength as high as 339.46MPa. Influences of C/SiC pins on the joining properties of C/SiC composites were studied. The shear strength and flexural strength of C/SiC-C/SiC joining are improved from 9.17MPa and 30.41MPa without pins to 20.06MPa and 75.03MPa with one C/SiC pin (diameter 2mm), respectively. The reliability of C/SiC-C/SiC joining is also improved with C/SiC pins in that the fracture mode changes from catastrophic without pins to non-catastrophic. The SEM photos show a strong bond between joining layer and C/SiC composites without obvious interface.

The effect of Vickers hardness indentations on the fracture mode in 8 mol% yttria-stabilised zirconia

2015 ◽  
Vol 50 (7) ◽  
pp. 2932-2943 ◽  
Author(s):  
Willy Vandermeulen ◽  
Rik-Wouter Bosch ◽  
Frans Snijkers
Keyword(s):  
Fracture Mode ◽  
Vickers Hardness

A Study on Reaction Bonded Ceramics Fabricated by Silicon Infiltration to B4C Preforms

2012 ◽  
Vol 724 ◽  
pp. 343-346 ◽  
Author(s):  
Rong Zhen Liu ◽  
Qing Wen Duan ◽  
Wen Wei Gu ◽  
Hai Yun Jin ◽  
Shao Chun Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Theoretical Result ◽  
Boron Carbide ◽  
Theoretical Calculation ◽  
Vickers Hardness ◽  
Volume Expansion ◽  
Maximum Density ◽  
Infiltration Process

Silicon was infiltrated into B4C preforms to fabricate B4C based composites ceramics at 1600 °C under vacuum circumstance. In this paper, silicon infiltration process was discussed by theoretical calculation. The volume expansion caused by reactions between silicon and boron carbide was about 89.1% from the calculation. In our study, the maximum density of B4C preform for the infiltration of silicon was about 1.5g/cm3 which was larger than theoretical result. The results of mechanical behavior showed that B4C based composites had excellent mechanical properties with a density lower than 2.6g/cm3, Vickers-hardness of this material was 27.2GPa, and this material showed a flexural strength of 349MPa and fracture toughness of 3.8 MPa*m1/2.

Evaluation of Mechanical Properties of Dental Feldsphatic Porcelains for Metal and Zirconia Core

2012 ◽  
Vol 727-728 ◽  
pp. 1104-1107
Author(s):  
Antonio Alves de Almeida-Junior ◽  
Gelson Luis Adabo ◽  
Beatriz Regalado Galvão ◽  
Diogo Longhini ◽  
Claudinei dos Santos
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
High Hardness ◽  
Hardness Test ◽  
Dental Prostheses ◽  
Significant Incidence ◽  
Significant Difference ◽  
Fixed Dental Prostheses ◽  
Intermediate Value

Studies has been reported a significant incidence of chipping of the feldspathic porcelain veneer in zirconia-based restorations. The purpose of this study was to compare the three-point flexural strength (MPa), Weibull parameters, Vickers hardness (VHN) and Vickers indentation fracture toughness (MPa/mm1/2) in feldspatic porcelains for metal and for zirconia frameworks. Bar specimens were made with the porcelains e.MaxCeram (EM) and VitaVM9 (V9) for zirconia core, and Duceragold (DG) and VitaVMK95 (VK) for metal core (n= 15). Kruskal-Wallis and Dun test were used for statistical analysis. There was no significant difference (p=0.31) among the porcelains in the flexural strength (Median= 73.2; 74.6; 74.5; 74.4). Weibull calculation presented highest reliability for VK (10.8) followed by EM (7.1), V9 (5.7) and DG (5.6). Vickers hardness test showed that EM (536.3), V9 (579.9) and VK (522.1) had no difference and DG (489.6) had the lowest value (p.001). The highest fracture toughness was to VK (1.77), DG (1.58) had an intermediate value while V9 (1.33) and EM (1.18) had the lowest values (p.001). Despite of the suitable flexural strength, reliability and high hardness, the porcelains used to zirconia-based fixed dental prostheses showed lower fracture toughness values.

Characterization of Mg-Al Sheet Clad Materials Fabricated by Hot Rolling

2007 ◽  
Vol 26-28 ◽  
pp. 409-412 ◽  
Author(s):  
Jae Seol Lee ◽  
Hyeon Taek Son ◽  
Ki Yong Lee ◽  
Soon Sub Park ◽  
Dae Guen Kim ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Vickers Hardness ◽  
Hot Rolling ◽  
High Strength ◽  
Interface Layer ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Clad Sheet ◽  
The Difference ◽  
Interface Layers

AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its mechanical properties were investigated in this study. The tensile strength and yield strength of Mg- Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083 Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the rolling directions. The thickness of interface layers between magnesium and aluminum materials increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling temperature was attributed to promote the diffusion between magnesium and aluminum materials. The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its thickness.

scholarly journals Influence of the Fiber Volume Content on the Durability-Related Properties of Polypropylene-Fiber-Reinforced Concrete

2020 ◽  
Vol 12 (2) ◽  
pp. 549
Author(s):  
Chenfei Wang ◽  
Zixiong Guo ◽  
Ditao Niu
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Volume Content ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Freeze Thaw ◽  
Chloride Environment ◽  
Polypropylene Fiber Reinforced Concrete

Polypropylene-fiber-reinforced concrete impacts the early shrinkage during the plastic stage of concrete, and the fiber volume content influences the durability-related properties of concrete. The purpose of this paper was to investigate the influence of fiber volume content on the mechanical properties, durability, and chloride ion penetration of polypropylene-fiber-reinforced concrete in a chloride environment. Tests were carried out on cubes and cylinders of polypropylene-fiber-reinforced concrete with polypropylene fiber contents ranging from 0% to 0.5%. Extensive data from flexural strength testing, dry–wet testing, deicer frost testing, and chloride penetration testing were recorded and analyzed. The test results show that the addition of the fiber improves the failure form of the concrete specimens, and 0.1% fiber content maximizes the compactness of the concrete. The flexural strength of specimen C2 with 0.1% fiber shows the highest strength obtained herein after freeze–thaw cycling, and the water absorption of specimen C2 is also the lowest after dry–wet cycling. The results also indicate that increasing the fiber volume content improves the freeze–thaw resistance of the concrete in a chloride environment. Chlorine ions migrate with the moisture during dry–wet and freeze–thaw cycling. The chlorine ion diffusion coefficient (Dcl) increases with increasing fiber content, except for that of specimen C2 in a chloride environment. The Dcl during freeze–thaw cycling is much higher than that during dry–wet cycling.

scholarly journals The Electrical Resistivity of a SiCw/Al Alloy Composite with Temperature

2004 ◽  
Vol 14 (7) ◽  
pp. 489-493
Author(s):  
Byung-Geol Kim ◽  
Shang-Li Dong ◽  
Su-Dong Park ◽  
Hee-Woong Lee
Keyword(s):  
Electrical Resistivity ◽  
Al Alloy ◽  
Alloy Composite
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