Download or read book High Shear Strain Rate Behavior of W Ni Fe Tungsten Heavy Alloy Composites as a Function of Matrix Volume Fraction written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of matrix volume fraction on the high shear strain-rate deformation and failure behavior of W-Ni-Fe heavy alloys is studied using the torsional Hopkinson bar apparatus. High strain-rate tests (at 700/s) were conducted using torsion specimens made from W-Ni-Fe alloys with three different matrix volume fractions. Different matrix volume fractions were obtained by changing the W content in the W-Ni-Fe alloy while keeping W grain size approximately constant. Experimental observations indicate that as the matrix volume fraction is decreased, the strain to failure decreases, at high rates of loading. There were no significant changes seen in the deformation behavior of the three materials at high shear strain-rate loading used in this study.
Download or read book Stress strain Behavior of Tungsten fiber reinforced Copper Composites written by David L. McDanels and published by . This book was released on 1963 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure Fracture Characteristics and Tensile Properties of Two Tungsten Heavy Alloys written by and published by . This book was released on 1995 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of microstructure on fracture behavior and tensile properties was investigated for two tungsten heavy alloys (93W-4.9Ni-2.1Fe and 91W-6Ni-3Co by weight-percentage) that are suitable materiai candidates for use as kinetic energy penetrators. Both alloys were evaluated in swaged and aged conditions. For comparable levels of swaging and aging, the W-Ni-Co alloy exhibited increased tensile strength and ductility compared to the W-Ni-Fe material. The W-Ni-Co alloy had a smaller average W grain size and a larger percentage of W in the matrix. Fracture surfaces of failed uniaxial tensile specimens tested at quasi-static and low-to-medium strain rates were characterized using scanning electron microscopy. The results indicate a strong relationship between microstructure, fracture behavior, and tensile properties as a function of alloy composition and strain rate. (MM).
Download or read book Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for Penetrator Application written by and published by . This book was released on 2005 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of fabrication process parameters, including conditions for powder preparation, sintering, cyclic heat-treatment, swaging, and annealing processes, on microstructures and static/dynamic mechanical properties of ODS tungsten heavy alloys were investigated. The composition of ODS tungsten heavy alloys was designed as 94W-4.56Ni-1.14Co-0.3Y2O3 which show the highest strength at similar microstructural parameters based on the analysis of microstructures and mechanical properties. The two-stage sintered ODS tungsten heavy alloy showed finer tungsten grain size than those prepared by conventional liquid phase sintering with similar matrix volume fraction and tungsten/tungsten contiguity. Cyclic heat-treatment process was introduced after sintering process to increase the tensile strength and elongation by decreasing the tungsten/tungsten contiguity. The swaging and annealing processes of ODS tungsten heavy alloy increase the tensile strength with decreasing the elongation. High strain rate dynamic compressive tests were performed by Hopkinson pressure bar test equipment. The dynamic compressive strength of ODS tungsten heavy alloys was improved by addition of oxide dispersoids and by modification of composition from W-Ni-Fe to W-Ni-Co. At the same time, the adiabatic shear bands induced by high strain rate dynamic shear tests became narrower by the dispersion of Y2O3 and by the composition modification. The 94W-4.56Ni-1.14Co-0.3Y2O3 alloy, which was two-stage sintered, cyclic heat-treated, swaged, and annealed, shows high ultimate tensile strength of 1350MPa, moderate elongation of 5% and high compressive yield strength of 1800MPa under a high strain rate deformation of 3000/s. The 94W-4.56Ni-1.14Co-0.3Y2O3 ODS tungsten heavy alloy has been suggested as an advanced core material for kinetic energy penetrators and hard target penetrators.
Download or read book Alloying Effects on Tungsten fiber reinforced Copper alloy Or High temperature alloy Matrix Composites written by Donald W. Pettrasek and published by . This book was released on 1963 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 1628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Localization in Tungsten Heavy Alloys Subjected to Shearing Deformations Under Superimposed High Pressures written by and published by . This book was released on 1995 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of investigations into the deformation and failure of tungsten-based composites (tungsten heavy alloys) at very high strain rates. Several new experimental techniques developed during the course of the work include pressure-shear recovery, allowing the recovery of samples subjected to high-rate shearing deformations; the dynamic measurement of radial strains, and the continuous measurement of projectile velocities. The experimental results showed that the development of adiabatic shear localization in tungsten heavy alloys is influenced by a superimposed hydrostatic pressure. Experimental characterizations have been performed of the very high-rate response of tungsten composites with tungsten-nickel-iron and hafnium matrices. It has been shown that these materials must be treated as dual-phase composites. The addition of a hard particulate reinforcement is shown to result in a substantial increase in matrix rate-sensitivity in a model metal-matrix composite. A simple modeling approach has been developed that allows one to predict the dynamic mechanical properties of a particle-reinforced metal-matrix composite given only the properties of the matrix phase. jg.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1998 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elevated temperature Tensile Properties of Alloyed Tungsten Fiber Composites written by Donald W. Petrasek and published by . This book was released on 1965 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of selected alloying elements on the elevated temperature tensile properties of tungsten fiber reinforced composites were studied. Composites were made of copper, copper- 2 percent chromium and copper- 10 percent nickel reinforced with various volume percents of uniaxially oriented tungsten fibers. The composites were tested in tension at temperatures up to 1800 degrees F.A comparison of the elevated-temperature tensile properties of tungsten fiber - copper alloy composites, representing soluble systems, was made with tungsten fiber - copper composites, representing a mutually insoluble system. The effects of alloying on the elevated-temperature tensile properties of tungsten fiber reinforced composites was also studied. A linear relation existed at elevated temperatures between tensile strength and volume percent fiber content for all the systems investigated. The copper alloy composites were weaker in tension at high volume percent fiber contents than copper composites in which alloying with the fiber did not occur. The tensile strength of the alloyed tungsten fiber decreased with increasing penetration of the alloying element into the tungsten fiber.
Download or read book Dynamic Strength and Strain Rate Effects on Fracture Behavior of Tungsten and Tungsten Alloys written by and published by . This book was released on 1991 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of the stress-strain response as a function of strain rate, spall strength, and dynamic fracture behavior of pure W, W-26Re, W-Ni-Fe and W-Ni-Fe-Co has been performed. Spall strength measurements, obtained in symmetric-impact tests, showed an increase in spall strength from 0.4 GPa for pure tungsten to 3.8 GPa for 90W- 7Ni-3Fe. Concurrent with increase in spall strength was a change in fracture mode from cleavage (for pure W) to a mixture of transgranular and intergranular fracture for the alloyed systems. Compression testing performed at strain rates from 10−3 s−1 to 3000 s−1 showed that pure tungsten exhibits a large strain rate sensitivity and almost no work hardening at tested strain rates. In contrast, W-26Re and W-Ni-Fe-Co displayed significant work hardening at all strain rates. 12 refs., 5 figs. 2 tabs.
Download or read book Development and Evaluation of High temperature Tungsten Alloys written by Armour Research Foundation (U.S.) and published by . This book was released on 1960 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Tungsten Composition on the Mechanical Properties on Thew ni fe Heavy Alloy written by Joseph W. O'Neil and published by . This book was released on 1965 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ductility and strength of W-Ni-Fe composites over a wide range of volume % W was investigated at room temperatures. A series of composites was prepared (40% W to 95% W), sintered in the presence of the liquid phase and tested in tension. The sources of strength and ductility of the W-Ni-Fe composite was determined as related to the measured dihedral angle, mean particle diameter, tungsten mean free path, tungsten contiguity and volume % W. Similar stress-strain curves were obtained for all specimens tested which showed liquid phase sintered microstructure. These test results indicate that the volume % has very little effect upon the composite strength. For W-Ni-Fe composites where the tungsten mean free path is greater than the measured particle diameter (approximately 85% to 96% W), the maximum strain and maximum stress at necking dropped off rapidly. (Author).
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tungsten Fiber Reinforced Copper Matrix Composites written by David L. McDanels and published by . This book was released on 1989 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Behavior of 97 2 W Alloy in Tension at High Temperatures written by John L. Green and published by . This book was released on 1994 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective was to investigate the behavior of 97.2% tungsten alloy in tension. A modified button head specimen was heated using resistive heating techniques. The affect high temperatures, medium strain rates, and heating rates had on the stress-strain results were observed. A high speed optical pyrometer and an optical clip gage were utilized for temperature and strain measurements. The optical clip gage could measure strain at strain rates up to 11.8/s. The room temperature experiments were at strain rates of 10-(exp 4)/s, 10-(exp 2)/s, and 5/s. The high heating rate experiments were at temperatures of 727 deg C, and 1097 deg C, heating rates of 5.4 deg C/sec and 536 deg C/sec and a strain rate of 5/s. Increase in yield point and flow stress were observed as the heating rate was increased. A modified Johnson-Cook (MJ+C) material model was proposed to include the effect of heating rate. The constants in the MJ+C model were determined based on the experimental results. Tungsten, High temperatures, Strain rate, Material modeling.
Download or read book Microstructure and Fracture Behavior of Tungsten Heavy Alloys written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The 93% W-5.6% Ni-1.4% Fe and 93.1% W-4.7% Ni-2.2% Co alloys (WHA) provided by Army Research Laboratory (ARL), Aberdeen are characterized to determine the effects of matrix alloying and swaging on the microstructure and fracture behavior. The W particles are oblong with respect to the swaging direction. The microstructure of the W-Ni-Fe alloy reveals good cohesive bonding between W particles, but there is W-matrix interface separation and matrix alloy cracking. The microstructure of the W-Ni-Co alloy reveals regions of good cohesive bonding between W particles, but also regions where some wetting has not occurred by the liquid. No evidence was observed of matrix alloy cracking. The fracture characteristic of WHA is dominantly cleavage of W particles.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1967-07 with total page 1270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
