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A simulation study on deformation behavior of
tungsten fiber reinforced copper matrix nanowire
Subodh Rana1 & Natraj Yedla2
1. Dept. of Metallurgical and Materials Engineering, NIT Jamshedpur
2. Dept. of Metallurgical and Materials Engineering, NIT Rourkela
TECHNICA ‘ 2014,
Introduction
Tungsten wirewww.gd-wholesale.com
Copper sheetwww.gd-wholesale.com
A
B
Tungsten fiber reinforced copper matrix compositewww.emeraldinsight.com
Interface
Matrix Fiber
C
Representative volume cell
• Fabricated by liquid phase infiltration.
•Continuous unidirectional tungsten fibers were packed in ceramic tubes to the desired fiber content.
•A slug of copper was placed above the fiber bundle, and the assembly was placed in a furnace and heated to 1478 K (2200 °F) for 1 hr in either a vacuum or hydrogen atmosphere.
Applications of W/Cu composite
• High Temperature aircraft- high creep resistant
• Rocket engine turbine
• High strength electrical conductor- strength by resistivity ratio 10 times higher than other
Takes initial
configuration
Calculates
potential
Obtain Force
Finds velocity
and position
Ends if last timestep is
reached
M D Simulation
Velocity-verlet integration with 2 fs timestepv(t+∆t)=v(t)+a(t)∆tr(t+∆t)=r(t)+v(t)∆t+1/2a(t)∆t
Gradient of potentialF=-dU/dr=ma
Taking configuration
and potential
method, EAM,
MEAM, tersoff, etc
Checks timestep
Simulation models and Parameters
Copper atom
Tungsten atom
Tungsten fiber reinforced copper nanowire
r=5Å
Copper nanowire before reinforcement
r=20Å
• Critical fiber length Lc = (σf*d)/2Tc = 2.2 nm{(16*5)/(2*18)= 2.2 }
•Rule of mixture: σc=σf*Vf +σm*Vm
Kc=Kf*Vf+Km*Vm
• There is insolubility between tungsten and copper
Results and discussions
at 0.5%/ps strain rateT= 300 K(G
pa)
(Å/ Å)
Engineering stress strain plot
• Increased in yield strength observed
• Presence of Tungsten Fiber delays the onset of necking
VMD snapshots at strain of 150 %
A B
Experimental Engineering strain stress curve(Review David L. McDanels, Lewis research centre, NASA, Tungsten Fiber Reinforced Copper Matrix Composites)
Comparison with experiment
Conclusions
• Reinforcement of Tungsten fiber increased the strength of the Cu matrix
•The yield strength of composite is ~4.5 Gpa
• The high strength to resistivity ratio makes it usable as high strength electrical conductor
• Use of this composite as structural component in space craft reduces its weight high strength by weight ratio
Refernces
[1] He, L.H., Lim, C.W., Wu, B.S., 2003. A continuum model for size-dependent deformation of elastic films of nano-scale thickness.Int.J.Solids Struct.41 (3–4), 847–857[2] University of Virginia, MSE 4270/6270: Introduction to Atomistic Simulations, Leonid Zhigilei[3] http://lammps.sandia.gov/doc/Manual.html[4] R.A. Johnson, Physics Rev, B37, 1988, 6121[5] http://www.crystallography.fr/mathcryst/twins.htm[6] Jeong-Won Kang and Ho-Jung Hwang, Mechanical deformation study of copper nanowire using atomistic simulation, Nanotechnology 12 (2001) 295–300[7] P.R. Subramanian and D.E. Laughlin, Cu-W (Copper Tungsten), Indian Institute of Metals, Calcutta, 1991, pp. 76-79[8] Dalvid-L. McDanels, Tungsten Fiber Reinforced Copper Matrix Composites, NASA Technical Paper 2924, 1989[9] David L. McDanels, Robert W. Jech, andJohn W. Weeton;Lewis Research Center Cleveland, Ohio, Stress-Strain Behaviour Of Tungsten-Fiber-Reinforced Copper Composites, NASA TN D-1881
Thank You