Processing of TiAl–Ti2AlN composites and their compressive properties

1992 ◽  
Vol 7 (4) ◽  
pp. 894-900 ◽  
Author(s):  
H. Mabuchi ◽  
H. Tsuda ◽  
Y. Nakayama ◽  
E. Sukedai
Keyword(s):  
Composite Materials ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Strength ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Combustion Reaction ◽  
Compressive Properties ◽  
Gaseous Nitrogen ◽  
The Matrix

Using elemental powders, combustion reaction was carried out to form intermetallic-ceramic composites in the Ti–Al–N system. Ti and Al powders reacted exothermically in gaseous nitrogen and formed a mixture product which had a fine distribution of the Ti2AlN particles in the matrix TiAl with a small amount of Ti3Al. Subsequently, these reacted products were arc-melted to obtain fully dense button ingots. The resulting composites had about 30 vol. % Ti2AlN, and the Ti2AlN particles were ellipsoidal or columnar in shape with sizes of 2–10 μm and appeared to be homogeneously distributed and well bonded to the matrix TiAl. It was found that such composite materials have a high strength at both room and elevated temperatures and some intrinsic compressive ductility at room temperature. Therefore, the processing technique in the present investigation is of interest as a new combustion reaction process to make intermetallic-based composite materials.

Evolution of Microstructure during Hot Deformation of the PM Molybdenum Alloy TZM

2007 ◽  
Vol 539-543 ◽  
pp. 2725-2730 ◽  
Author(s):  
T. Mrotzek ◽  
Andreas Hoffmann ◽  
U. Martin ◽  
H. Oettel
Keyword(s):  
Yield Strength ◽  
Hot Deformation ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Strength ◽  
Tensile Tests ◽  
Primary Recrystallization ◽  
Molybdenum Alloy ◽  
Texture Formation ◽  
Evolution Of Microstructure

The molybdenum alloy TZM (Mo-0.5wt%Ti-0.08wt%Zr) is a commonly used structural material for high temperature applications. For these purposes a high strength at elevated temperatures and also a sufficient ductility at room temperature are being aimed. Preceding investigations revealed the existence of subgrains in hot deformed TZM. It was observed that with proceeding primary recrystallization and therefore with disappearance of subgrains the yield strength drops almost to a level of pure molybdenum. It is being assumed that the existence of a dislocation substructure has a pronounced effect on the yield strength of TZM. The aim of the present study was to evaluate the subgrain and texture formation and also to estimate the dislocation arrangement within subgrains during hot deformation. Hence, TZM rods were rolled to different degrees of deformation at a temperature above 0.5 Tm. The microstructure of the initial material was fully recrystallized. Texture formation, misorientation distributions and subgrain sizes were analyzed by electron backscattering diffraction (EBSD). Mechanical properties were characterized by tensile tests at room temperature and up to 1200°C. It was revealed, that with increasing degree of deformation a distinct substructure forms and therefore yield strength rises. Consequently, the misorientation between adjacent subgrains increases, their size decreases and a <110> fibre texture develops. To estimate the influence of texture on strength of TZM the Taylor factors are calculated from EBSD data.

Effect of Stress Relaxation on Springback of Steel Sheet in Warm Forming

2016 ◽  
Vol 725 ◽  
pp. 671-676 ◽  
Author(s):  
Naoko Saito ◽  
Mitsugi Fukahori ◽  
Daisuke Hisano ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida
Keyword(s):  
Stress Relaxation ◽  
High Strength Steel ◽  
Room Temperature ◽  
Steel Sheet ◽  
Elevated Temperatures ◽  
High Strength ◽  
Warm Forming ◽  
Sheet Metals ◽  
Stress Relaxation Behavior ◽  
Increasing Temperature

Springback of a high strength steel (HSS) sheet of 980 MPa grade was investigated at elevated temperatures ranging from room temperature to 973 K. From U-and V-bending experiments it was found that springback was decreased with increasing temperature at temperatures of above 573 K. Furthermore, springback was decreased with punch-holding time because of stress relaxation. In this work, the stress relaxation behavior of the steel was experimentally measured. By using an elasto-vicoplasticity model, the stress relaxation was described, and its effect on the springback of sheet metals in warm forming was discussed theoretically.

Investigating thiol-epoxy composites for semiconductor die attach adhesives

2015 ◽  
Vol 1718 ◽  
pp. 27-31
Author(s):  
Andrew Wei ◽  
Radu Reit ◽  
Walter Voit
Keyword(s):  
Shear Strength ◽  
Tensile Testing ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Epoxy Polymer ◽  
Processing Technique ◽  
Adhesion Promoters ◽  
Lap Shear ◽  
Die Attach ◽  
Polymer Adhesive

ABSTRACTIn this study, thiol-epoxy polymer composites are explored as candidates for high-temperature die attach applications. We present a polymer composite processing technique for die attach adhesives with low cure-stress. Lap shear samples of both a polymer adhesive and current industry adhesives were subjected to tensile testing and die shear strength was compared. At 260 °C, the candidate polymer adhesive exhibited a die shear strength of 0.500 MPa in comparison with 1.35 MPa and 0.258 MPa for two control adhesives. While samples showed less variation in properties in die shear strength between room temperature and 260 °C, the absolute die shear strength values were inferior to commercial adhesives at both room and elevated temperatures. We hypothesize that low cure stress networks, such as the thiol-epoxies presented, provide a compelling choice to engineer new die attach adhesives, but realize that further network refining is needed including the addition of adhesion promoters and other additives, a task better suited to industrial research with a focus in properties optimization.

scholarly journals Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

2017 ◽  
Vol 17 (3) ◽  
pp. 73-78 ◽  
Author(s):  
A. Kurzawa ◽  
J.W. Kaczmar
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Elevated Temperatures ◽  
Al Alloy ◽  
Pressure Infiltration ◽  
Reinforcing Particles ◽  
Strength Based ◽  
Crack Mechanics ◽  
The Matrix ◽  
Microscopic Studies

AbstractThe paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3particles of 3-6μm with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by volume) at an ambient of 23°C and at elevated temperatures to a maximum of 300°C. The results of this study were referred to the unreinforced matrix EN AC-44200 and to its hardness and tensile strength. Based on microscopic studies, an analysis and description of crack mechanics of the tested materials were performed. Structural analysis of a fracture surface, material structures under the crack surfaces of the matrix and cracking of the reinforcing particles were performed.

The Room Temperature and Elevated Temperature Fracture Toughness Response of Alloy A-286

1978 ◽  
Vol 100 (2) ◽  
pp. 195-199 ◽  
Author(s):  
W. J. Mills
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Second Phase ◽  
Surface Micromorphology ◽  
Second Phase Particles ◽  
The Matrix ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Base Superalloy

The elastic-plastic fracture toughness (JIc) response of precipitation strengthened Alloy A-286 has been evaluated by the multi-specimen R-curve technique at room temperature, 700 K (800°F) and 811 K (1000°F). The fracture toughness of this iron-base superalloy was found to decrease with increasing temperature. This phenomenon was attributed to a reduction in the materials’s strength and ductility at elevated temperatures. Electron fractographic examination revealed that the overall fracture surface micromorphology, a duplex dimple structure coupled with stringer troughs, was independent of test temperature. In addition, the fracture resistance of Alloy A-286 was found to be weakened by the presence of a nonuniform distribution of second phase particles throughout the matrix.

scholarly journals Mechanical Characterization and Finite Element Analysis of Jute-Epoxy Composite

2018 ◽  
Vol 144 ◽  
pp. 02014 ◽  
Author(s):  
Rajole Sangamesh ◽  
Naveen Kumar ◽  
K. S. Ravishankar ◽  
S. M. Kulkarni
Keyword(s):  
Composite Materials ◽  
Mechanical Characterization ◽  
Natural Fiber ◽  
Fiber Composite ◽  
High Strength ◽  
Sem Analysis ◽  
Element Analysis ◽  
Practical Applications ◽  
The Matrix ◽  
Natural Fiber Composite

Natural fiber composite materials are such an appropriate material, that replaces synthetic composite materials for many of practical applications where we need high strength and low density. Natural fiber composites combine the technological, ecological and economical aspects. This leads to discovering its vast applications in the aeronautics, automotive, marine and sporting sectors. This paper deals with the study on mechanical characterization (Tensile, Compression and Flexural) of jute/epoxy (JE) polymer composite. The flexural properties of composites are experimentally tested and are simulated in commercially available FEA software. Flexural tested results are in good agreement with FEA results. Scanning electron microscopy (SEM) analysis of the failed samples reveals the matrix dominated failure.

Effects of Additives on the Interfacial Microstructure of SiC Fiber/Li2O-Al2O3-6SiO2 Glass-Ceramic Composites

1991 ◽  
Vol 49 ◽  
pp. 924-925
Author(s):  
J.Y. Hsu ◽  
Y. Berta ◽  
R.F. Speyer
Keyword(s):  
Flexural Strength ◽  
Glass Ceramic ◽  
Elevated Temperatures ◽  
Ceramic Composites ◽  
Interfacial Microstructure ◽  
High Fracture Toughness ◽  
Matrix Composition ◽  
High Fracture ◽  
Sic Fiber ◽  
The Matrix

SiC fiber reinforced lithia-alumina-silica glass-ceramic composites have exhibited superior mechanical properties at room and elevated temperatures. The flexural strength of these composites is 3 to 4 times larger than that of monolithic glass-ceramics. The high flexural strength of these composites is due to the transfer of the applied load from the matrix to the stronger and stiffer SiC fiber reinforcement. These composites also have demonstrated very high fracture toughness, KIC (critical stress intersity factor) values of ∼ 17 MPa m1/2, which is attributed to an amorphous carbon-rich interfacial layer between the fiber and matrix. Nb2O2 has been added to the matrix composition in order to develop a NbC layer outside the amorphous C-rich layer after thermal processing, thereby buffering the fiber/matrix reactivity (avoid carbon forming CO gas which would deteriorate the matrix).

SPECIAL GENCO

Alloy Digest ◽  
1965 ◽  
Vol 14 (2) ◽  
Keyword(s):  
Stainless Steel ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Steel Company ◽  
Temperature Range ◽  
Temperature Performance ◽  
Corrosion And Oxidation ◽  
Chromium Stainless Steel

Abstract Special Genco is a hardenable 12% chromium stainless steel developed for applications requiring superior strength to Type 403 stainless steel at elevated temperatures. This grade retains high strength and exhibits excellent ductility over the temperature range from room temperature to 1200 F. Special Genco provides excellent resistance to corrosion and oxidation within this temperature range. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-165. Producer or source: Latrobe Steel Company.

MODELING THE ACCUMULATION OF DAMAGES AND THE FAILURE OF CERAMIC COMPOSITES Al2O3-ZrO2, OBTAINED BY ADDITIVE TECHNOLOGIES, UNDER HIGH-SPEED LOADING

2021 ◽  
pp. 140-157
Author(s):  
V.V. Promakhov ◽  
◽  
M.V. Korobenkov ◽  
N.A. Schultz ◽  
A.S. Zhukov ◽  
...  
Keyword(s):  
Crack Resistance ◽  
High Speed ◽  
High Strength ◽  
Nonlinear Effects ◽  
Ceramic Composites ◽  
Additive Technologies ◽  
The Matrix ◽  
Mesoscopic Level ◽  
Martensitic Phase Transformations ◽  
Strengthening Particles

Functional ceramic composite materials are widely used in industry due to their high strength, hardness, high operating temperature, and chemical inertness. Among the most famous types of functional ceramics are the ceramic composites based on the Al2O3-20% ZrO2 system. In this work, the effect of the loading rate on the crack resistance is studied as well as the effect of the crack resistance of ceramic composites Al2O3-20% t-ZrO2 with a mass content of submicron tZrO2 particles on the high-speed compression of model specimens in shock waves and on the high-speed tension in the region of interaction of unloading waves. It is established that nonlinear effects of the mechanical behavior of ceramic composites ZrO2-Al2O3 with a transformationhardened matrix obtained by additive technologies are manifested at shock loading amplitudes close to or exceeding the Hugoniot elastic limit. Nonlinear effects under intense dynamic impacts on the considered composites are associated with the processes of self-organization of deformation regimes at a mesoscopic level, as well as with the occurrence of martensitic phase transformations in the matrix volumes, which are adjacent to strengthening particles. The modeling approach presented in this work can be used to determine the dynamic characteristics of ceramic composites up to shock loads of 1000 m/s.

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