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High-pressure shock behavior of WC and Ta2O5 powders.

Description: Planar shock experiments were conducted on granular tungsten carbide (WC) and tantalum oxide (Ta{sub 2}O{sub 5}) using the Z machine and a 2-stage gas gun. Additional shock experiments were also conducted on a nearly fully dense form of Ta{sub 2}O{sub 5}. The experiments on WC yield some of the highest pressure results for granular materials obtained to date. Because of the high distention of Ta{sub 2}O{sub 5}, the pressures obtained were significantly lower, but the very high temperatures generated led to large contributions of thermal energy to the material response. These experiments demonstrate that the Z machine can be used to obtain accurate shock data on granular materials. The data on Ta{sub 2}O{sub 5} were utilized in making improvements to the P-{lambda} model for high pressures; the model is found to capture the results not only of the Z and gas gun experiments but also those from laser experiments on low density aerogels. The results are also used to illustrate an approach for generating an equation of state using only the limited data coming from nanoindentation. Although the EOS generated in this manner is rather simplistic, for this material it gives reasonably good results.
Date: October 1, 2011
Creator: Knudson, Marcus D. (Sandia National Laboratories, Albuquerque, NM); Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John & Root, Seth (Sandia National Laboratories, Albuquerque, NM)
Partner: UNT Libraries Government Documents Department

Crush Grinding

Description: Crush Grinding is a special process used at the Kansas City Plant to finish stem sections of reservoir products. In this process, a precise profile of the desired product is formed on a tungsten carbide roll. This roll slowly transfers a mirror image of the profile onto the grinding surface of a wheel. The transfer rate of the profile is between 0.001 and 0.010 inches per minute. Crush grinding is desirable since it provides consistent surface finishes and thin walls at a high production rate. In addition, it generates very sharp fillet radii. However, crush grinding is a complex process since many variables affect the final product. Therefore, the process requires more attention and knowledge beyond basic metal removal practices. While the Kansas City Plant began using these machines in 1995, a formal study regarding crush grinding has not been conducted there. In addition, very little literature is available in the grinding industry regarding this process. As a result, new engineers at the Kansas City Plant must learn the process through trial and error. The purpose of this document is to address this literature deficit while specifically promoting a better understanding of the stem crush grinding process at the Kansas City Plant.
Date: April 1, 2005
Creator: Nguyen, T. Q.
Partner: UNT Libraries Government Documents Department

Dynamic compaction of tungsten carbide powder.

Description: The shock compaction behavior of a tungsten carbide powder was investigated using a new experimental design for gas-gun experiments. This design allows the Hugoniot properties to be measured with reasonably good accuracy despite the inherent difficulties involved with distended powders. The experiments also provide the first reshock state for the compacted powder. Experiments were conducted at impact velocities of 245, 500, and 711 m/s. A steady shock wave was observed for some of the sample thicknesses, but the remainder were attenuated due to release from the back of the impactor or the edge of the sample. The shock velocity for the powder was found to be quite low, and the propagating shock waves were seen to be very dispersive. The Hugoniot density for the 711 m/s experiment was close to ambient crystal density for tungsten carbide, indicating nearly complete compaction. When compared with quasi-static compaction results for the same material, the dynamic compaction data is seen to be significantly stiffer for the regime over which they overlap. Based on these initial results, recommendations are made for improving the experimental technique and for future work to improve our understanding of powder compaction.
Date: April 1, 2005
Creator: Gluth, Jeffrey Weston; Hall, Clint Allen; Vogler, Tracy John & Grady, Dennis Edward
Partner: UNT Libraries Government Documents Department

Bonding of WC with an iron aluminide (FeAl) intermetallic

Description: FeAl, which has high oxidation and sulfidation resistance, was shown to be thermodynamically compatible with WC. Calculations indicate that soly. of WC in liq. Fe-40at.%Al at 1450 C is about 2 at.%. Since liquid FeAl wets WC very well, the WC/FeAl system lends itself to liquid-phase sintering, resulting in close to theoretical densities. Almost fully dense cermets with 20.6 wt% FeAl binder were produced. With one-step infiltration, 98% dense cermets with only 7 wt% FeAl binder were fabricated. RT bend strengths and fracture toughness for WC-20.6 wt% FeAl reached 1680 MPa and 22 MPa{center_dot}m{sup 1/2}. Ductile binder fracture was observed on the fracture surfaces. Pores containing oxide inclusions were found, suggesting that improvements in processing are likely to further improve the mechanical properties. Insufficient process control may explain why WC/FeAlNi cermets did not show improved mechanical properties, although Ni strengthens FeAl. For WC bonded with FeAl, mechanical properties were measured at RT and 800 C. Bend strengths at 800 C in air increased with WC volume fraction, and fracture toughness were higher than at RT.
Date: August 1, 1996
Creator: Schneibel, J. H. & Subramanian, R.
Partner: UNT Libraries Government Documents Department

Machinability study of Aermet 100

Description: Machinability of Aermet 100, an ultrahigh strength alloy developed for Navy by Carpenter Technology as a candidate material for aircraft landing gear application, was studied by performing single-point turning tests. Coated and uncoated carbides, ceramic, and cermet cutting tool inserts of a square geometry (SNG 432 type) were used. Round stock workpieces were tested in the as - received, unaged condition and without using any cutting fluid. The turning tests for each tool material were conducted by (i) first establishing the cutting conditions that would allow the continued generation of broken chips during a given cutting test, (ii) measuring intermittently the flank wear as a function of cutting time under such established cutting conditions for discontinuous broken chips, and (iii) determining the tool life using the criteria specified in the ISO Standard 3685: 1993(E). Cutting tools except some uncoated carbide and ceramic were used with a mechanical chip breaker to induce chip breakage and avoid the generation of long continuous chips. The results obtained include the optimal cutting conditions for discontinuous chips, tool wear - cutting time curves, and records of tool life and tool failure mode for each tool material. From the measured tool life and cutting conditions, the amount of material removed by each cutting material was calculated. Coated carbide with CVD tri-phase coating showed the longest tool life that exceeded the twelve minute criterion and removed the highest amount of material per tool. Other tools failed by cutting edge chipping and their lives were shorter.
Date: February 8, 1995
Creator: Squire, D. V.; Syn, C. K. & Fix, B. L.
Partner: UNT Libraries Government Documents Department

Micromilling of Metal Alloys with Focused Ion Beam-Fabricated Tools

Description: This work combines focused ion beam sputtering and ultra-precision machining as a first step in fabricating microstructure in metals and alloys. Specifically, {approx}25{micro}m diameter micro-end mills are made from cobalt M42 high-speed steel and C2 micrograin tungsten carbide tool blanks by ion beam sputtering. A 20 keV focused gallium beam defines tool cutting edges having radii of curvature < 0.1{micro}m. Micro-end mills having 2, 4 and 5 cutting edges successfully machine small trenches in 6061-T4 aluminum, brass, 4340 steel and polymethyl methacrylate. Machined trench widths are approximately equal to the tool diameters and surface roughnesses (rms) are {approx}150 nm or less. Microtools are robust and operate for more than 6 hours without fracture. Results from ultra-precision machining aluminum at feed rates as high as 50 mm/minute are included.
Date: November 5, 1999
Creator: ADAMS,DAVID P.; VASILE,M.J.; BENAVIDES,GILBERT L. & CAMPBELL,ANN N.
Partner: UNT Libraries Government Documents Department

Mapping residual stresses after foreign object damage using the contour method

Description: A 51-mm thick plate of High-Strength Low-Alloy (HSLA-100) steel was impacted by a 6.4 mm diameter tungsten carbide sphere traveling at 2.2 km/sec. The projectile penetration left a 10 mm diameter and 12 mm deep crater. A residual stress map over a cross-section through the crater was measured by the contour method. The predominant feature of the stress map was a peak compressive stress of 900 MPa, or 1.3 times the yield strength, centered about 1.5 crater radii below the crater floor. The results were compared with an explicit finite element simulation of the impact event. The model has good agreement with the measured residual stresses. As part of the study, residual stresses in the as-received HSLA-100 plate were also measured and found to be a typical quenching stress distribution with peak compressive stress of about 165 MPa a few mm below the surface and tensile stress of 200 MPa in the center of the plate thickness.
Date: January 1, 2002
Creator: Prime, M. B. (Michael B.) & Martineau, R. L. (Rick L.)
Partner: UNT Libraries Government Documents Department

Pressure-shear experiments on granular materials.

Description: Pressure-shear experiments were performed on granular tungsten carbide and sand using a newly-refurbished slotted barrel gun. The sample is a thin layer of the granular material sandwiched between driver and anvil plates that remain elastic. Because of the obliquity, impact generates both a longitudinal wave, which compresses the sample, and a shear wave that probes the strength of the sample. Laser velocity interferometry is employed to measure the velocity history of the free surface of the anvil. Since the driver and anvil remain elastic, analysis of the results is, in principal, straightforward. Experiments were performed at pressures up to nearly 2 GPa using titanium plates and at higher pressure using zirconium plates. Those done with the titanium plates produced values of shear stress of 0.1-0.2 GPa, with the value increasing with pressure. On the other hand, those experiments conducted with zirconia anvils display results that may be related to slipping at an interface and shear stresses mostly at 0.1 GPa or less. Recovered samples display much greater particle fracture than is observed in planar loading, suggesting that shearing is a very effective mechanism for comminution of the grains.
Date: October 1, 2011
Creator: Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Thornhill, Tom Finley, III (, Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John & Alexander, C. Scott (Sandia National Laboratories, Albuquerque, NM)
Partner: UNT Libraries Government Documents Department

Elevated Temperature Sensors for On-Line Critical Equipment Health Monitoring

Description: The objective of the program was to improve high temperature piezoelectric aluminum nitride (AlN) sensor technology to make it useful for instrumentation and health monitoring of current and future electrical power generation equipment. Improvements were aimed primarily at extending the useful temperature range of the sensor from approximately 700 C to above 1000 C, and investigating ultrasonic coupling to objects at these temperatures and tailoring high temperature coupling for use with the sensor. During the project, the chemical vapor deposition (CVD) AlN deposition process was successfully transferred from film production on tungsten carbide substrates to titanium alloy and silicon carbide (SiC) substrates. Film adhesion under thermal cycling was found to be poor, and additional substrate materials and surface preparations were evaluated. A new, porous SiC substrate improved the performance but not to the point of making the films useful for sensors. Near the end of the program, a new family of high temperature piezoelectric materials came to the attention of the program. Samples of langasite, the most promising member of this family, were obtained and experimental data showed promise for use up to the 1000 C target temperature. In parallel, research successfully determined that metal foil under moderate pressure provided a practical method of coupling ultrasound at high temperature. A conceptual sensor was designed based upon these methods and was tested in the laboratory.
Date: March 31, 2006
Creator: Sebastian, James
Partner: UNT Libraries Government Documents Department

IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

Description: In this reporting period, the project focused on the investigations of FM material container-less HIPping, disc section examination and heat treatment, and full disc manufacture. The FM container-less HIPping resulted in either full density not being reached or reaching full density but losing the FM structure. Container HIPping seems to be necessary to consolidate the FM material. The heat treatment conducted on the 6.5 inch disc section with a WC insert caused cracking in the WC body and along the WC and H13 boundary. Two full 6.5 inch disc cutters were produced but contained defects. It is planned to produce more full disc cutters in the next quarter.
Date: May 1, 2003
Creator: Huang, Xiaodi & Gertsch, Richard
Partner: UNT Libraries Government Documents Department

FeAl-TiC and FeAl-WC composites - melt infiltration processing, microstructure and mechanical properties

Description: TiC-based and WC-based cermets were processed with iron aluminide, an intermetallic, as a binder by pressureless melt infiltration to near full density (> 97 % theoretical density). Phase equilibria calculations in the quaternary Fe-Al-Ti-C and Fe-Al-W-C systems at 145{degrees}C were performed to determine the solubility of the carbide phases in liquid iron aluminide. This was done by using Thermocalc{trademark} and the results show that molten Fe-40 at.% Al in equilibrium with Ti{sub 0.512}C{sub 0.488} and graphite, dissolves 4.9 at% carbon and 64 atomic ppm titanium. In the Fe-Al-W-C system, liquid Fe-40 at.% Al in equilibrium with graphite dissolves about 5 at.% carbon and 1 at.% tungsten. Due to the low values for the solubility of the carbide phases in liquid iron aluminide, liquid phase sintering of mixed powders does not yield a dense, homogeneous microstructure for carbide volume fractions greater than 0.70. Melt infiltration of molten FeAl into TiC and WC preforms serves as a successful approach to process cermets with carbide contents ranging from 70 to 90 vol. %, to greater than 97% of theoretical density. Also, the microstructures of cermets prepared by melt infiltration were very homogeneous. Typical properties such as hardness, bend strength and fracture toughness are reported. SEM observations of fracture surfaces suggest the improved fracture toughness to result from the ductility of the intermetallic phase. Preliminary experiments for the evaluation of the oxidation resistance of iron aluminide bonded cermets indicate that they are more resistant than WC-Co cermets.
Date: April 1, 1997
Creator: Subramanian, R. & Schneibel, J.H.
Partner: UNT Libraries Government Documents Department

Neutron scattering characterization of microstructure in uranium silicides, ceramic composites and Ni-based alloys

Description: Neutron scattering has proven to be a valuable tool for studying the microstructural properties of technologically important materials. The exceptionally high penetration power of neutrons enables the investigation of bulk materials, while unusual scattering contrasts observed in many materials provide unique access to important properties. Macroscopic performance of components under extreme conditions, which ultimately determines their viability for special applications, is often closely related to microstructural properties such as particle size, residual stress and phase stability. Neutron scattering experiments performed with samples exposed to realistic environmental conditions provide direct correlation between microscopic and macroscopic properties. Neutron irradiation of uranium silicide (a prospective reactor fuel), is used here as a prototypical example of in situ residual stress generation and evolution, accompanied by direct amorphization. Neutron diffraction studies at IPNS identified structural instabilities which contributed to material failure. Highly accurate measurements of residual strains in ceramic composites are used to validate computer models for stress variation with temperature and the effects of interfacial fiber coatings on residual stress. Coarsening and lattice mismatch of {gamma}{prime}-type Ni{sub 3}(Al,Si) particles in Ni-based alloys, which strongly influence coherency strains in these materials, are also measured directly using neutron scattering.
Date: October 1, 1997
Creator: Richardson, J.W. Jr.
Partner: UNT Libraries Government Documents Department

IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

Description: A tungsten carbide monolithic preform was produced by Advanced Ceramics. MTU conducted various sintering tests on the preform to determine conditions for removing the organic binder and improving the mechanical properties. The originally selected parameters for sintering did not perform as anticipated and further testing is underway.
Date: July 27, 2001
Creator: Huang, Xiaodi & Gertsch, Richard
Partner: UNT Libraries Government Documents Department

Ion Beam Sputter Fabrication of Micro-Grooving and Micro-Threading Tools

Description: This paper presents techniques for fabricating microscopic, nonplanar features in a variety of materials. Micro-grooving and micro-threading tools having cutting dimensions of 10-30{micro}m are made by focused ion beam sputtering and used in ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide. This creates cutting edges having radii of curvature less than 0.4 {micro}m, and rake features similar to conventional lathe tools. Clearance for minimizing frictional drag of a tool results from the sputter yield dependence on ion herd target incidence angle. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close matching between tool width and feature size. Microtools controllably machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061-T6 Al cylindrical substrates. Micro-grooving tools also fabricate sinusoidal waveform features in polished metal substrates.
Date: November 5, 1999
Creator: ADAMS,DAVID P.; VASILE,M.J. & KRISHNAN,A.S.M.
Partner: UNT Libraries Government Documents Department

IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

Description: During this reporting period, we mainly focused on solving the disc distortion problem that was encountered in the last quarter. A slower heating rate during off-gassing was tested to reduce the HIPping can expansion. However, slight expansion still occurred. Two 6.5 inch discs were produced with many defects. One was made of H13 powder only and the other was made of H13 powder with WC inserts. It was believed that the defects were caused by the slight expansion of the HIP can during the elevated temperature off-gassing and a vacuum leak in the HIPping can.
Date: March 18, 2004
Creator: Huang, Xiaodi & Gertsch, Richard
Partner: UNT Libraries Government Documents Department

NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

Description: The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.
Date: January 31, 2006
Creator: Radtke, Robert
Partner: UNT Libraries Government Documents Department

OCRWM SCIENCE & TECHNOLOGY PROGRAM MATERIALS PERFORMANCE TARGETED THRUST FACT SHEET

Description: In severe corrosive or abrasive environments, steel is rarely used since the range of properties available, in existing steels, are insufficient, resulting in the prevalent usage of either corrosion resistant materials like nickel based superalloys or abrasion resistant materials like tungsten carbide based hardmetals. Recently, a host of carbide based alloys including WC-Co-Cr, NiCr-Cr{sub 3}C{sub 2}, WC-Cr{sub 3}C{sub 2}-Ni etc. have been developed in an attempt to bridge the gap between providing both wear and corrosion protection. In this presentation, data will be presented showing how a newly developed steel coating, SAM2X5, with an amorphous/nanocomposite structure can bridge the gap between conventional metallic alloys and ceramic hardmetal performance with excellent combinations of properties including corrosion resistance superior to nickel superalloys in a number of environments and wear resistance approaching that of tungsten carbide cobalt. The unique combination of damage tolerance developed should be especially applicable for the replacement of electrolytic hard chromium.
Date: October 6, 2005
Creator: DOE
Partner: UNT Libraries Government Documents Department

LIFE Chamber Chemical Equilibrium Simulations with Additive Hydrogen, Oxygen, and Nitrogen

Description: In order to enable continuous operation of a Laser Inertial confinement Fusion Energy (LIFE) engine, the material (fill-gas and debris) in the fusion chamber must be carefully managed. The chamber chemical equilibrium compositions for post-shot mixtures are evaluated to determine what compounds will be formed at temperatures 300-5000K. It is desired to know if carbon and or lead will deposit on the walls of the chamber, and if so: at what temperature, and what elements can be added to prevent this from happening. The simulation was conducted using the chemical equilibrium solver Cantera with a Matlab front-end. Solutions were obtained by running equilibrations at constant temperature and constant specific volume over the specified range of temperatures. It was found that if nothing is done, carbon will deposit on the walls once it cools to below 2138K, and lead below 838K. Three solutions to capture the carbon were found: adding pure oxygen, hydrogen/nitrogen combo, and adding pure nitrogen. The best of these was the addition of oxygen which would readily form CO at around 4000K. To determine the temperature at which carbon would deposit on the walls, temperature solutions to evaporation rate equations needed to be found. To determine how much carbon or any species was in the chamber at a given time, chamber flushing equations needed to be developed. Major concerns are deposition of carbon and/or oxygen on the tungsten walls forming tungsten oxides or tungsten carbide which could cause embrittlement and cause failure of the first wall. Further research is needed.
Date: September 3, 2009
Creator: DeMuth, J A & Simon, A J
Partner: UNT Libraries Government Documents Department