Master's Abstract ID# 1354
Graduate Category: Engineering and Technology Degree Level: Master’s Abstract ID# 1354
Impact Mechanics of Micron Scale Metal Particles Carried by a Supersonic Jet Results: Impact with a hard substrate
Abstract • This work is motivated by the Cold Spray technology which is currently used to deposit thick metal coatings, with the potential to achieve 3D-printed, load bearing components. • We report the deformation characteristic of micron scale (~20 µm) metal (Al-6061) particles in high velocity impacts (102-103 m/s) with hard (sapphire) and deformable (Al6061) surfaces. • The particles rebound from the hard substrate but bond with the metal substrate if the conditions are “right.” • Under these conditions the material experiences strain rates (107 – 108) causing severe plastic deformation. It is well known that under such high strain rates, the flow (yield) stress of the material increases. • Experiments conducted by collaborators and theoretical analysis by FEM were used to investigate the impact mechanics. • It was shown that a bilinear JC-model is suitable to predict the deformation characteristics of a single particle, impacting a zirconium surface at room temperature. • Scraping tests of aluminum particles impacting the deformable substrate showed that particles tend to shear off in the middle, rather than the substrate-particle interface. • Results of this ongoing work are useful in uncovering the fundamental mechanics of particle bonding in the Cold Spray technology.
V = 663 m/s
• Experiments and simulations shows that the particles does not separate from the substrate, however, they are breaking due to the shear forces. • Peak values of the horizontal reaction force in both experiments and simulations are on the same order of magnitude and they are around 0.128 N
V = 699 m/s
In bilinear Johnson-Cook Model, as the plastic strain rate increases, the yield stress of the material rises more. Consequently, the material behaves harder and deforms less. That’s why they look very similar to experiments. The Classic Johnson-Cook model, cannot predict dynamic behavior of material precisely, in high strain rate phenomena (more than 1e4 /s)
Conclusions • Bilinear JC model is an appropriate model to anticipate the mechanical behavior of a dynamic impact problem, especially in Cold Spray applications. • In debonding simulations and experiments, it is observed that the interface strength of the bonding is stronger than yield strength of the material. • Simulations show that the COF has almost no effect on any of the metrics, regardless of the impact velocity.
Vr/Vi
0.15 0.1
0 0
200
400
Vi, m/s
600
800
References
JC-4 [2]
0.2215 0.002
JC-5 [1]
270
138.2
0.1792 0.002
𝒏
𝑪𝑪
C2
if ε p < εc if ε p > εc 𝜺̇ 𝒄
0.1301
𝒎
1.34
𝑻𝒎 , K 925
597.2
0.1301
1.34
925
597.2
A,B,n,C,m are the JC material parameters measured at or below the transition temperature T,TR,Tm are the current temperature, Room temperature and melting temperature is the equivalent plastic strain rate 𝜀𝑝· is the reference strain rate 𝜀0·
* All material properties are temperature dependent, however, properties in the room temperature are just reported here.
•
•
This transition occurs fast in soft substrate and has some delay in hard substrate. In general, CoF locks the amount of particle spreading on the substrate and helps to achieve more realistic results.
µ = 0.05
µ = 0.5
0.07
µ = 0.8
Al-Glass, 699 m/s, 23.4 um
0.06
R² = 0.9057
0.05 0.04 0.03
R² = 0.9993
0.02
COR
0.01
Poly. (COR)
0
Contact Area Poly. (Contact Area)
180 160 140 120 100 80 60 40 20 0
[1] Manes, A., et al. (2011). Analysis of strain rate behavior of an Al 6061 T6 alloy. Procedia Engineering, 10, 3477-3482. [2] Manes, A., et al. (2013). An experimental–numerical investigation on aluminum tubes subjected to ballistic impact with soft core 7.62 ball projectiles. Thin-Walled Structures 73 6880. [3] Lesuer, D. et al. (1999). Modeling large strain, high rate deformation in metals. Engineering Research, Development and Technology. [4] Manes, A., et al. (2011). Analysis of strain rate behavior of an Al 6061 T6 alloy. Procedia Engineering, 10, 3477-3482. [5] Dina Goldbaum, J. Michael Shockley, Richard R. Chromik, Ahmad Rezaeian, Stephen Yue, Jean-Gabriel Legoux, and Eric Irissou. “The Effect of Deposition Conditions on Adhesion Strength of Ti and Ti6Al4V Cold Spray Splats”Journal of thermal spray technology(2011)
0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
COF
AL particle on AL substrate µ = 0.05
µ = 0.5
µ = 0.8
0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0
Al-Al, 699 m/s, 23.4 um R² = 0.9977
4.1 4
Contact Area um^2
1 C= 1 and ε 0 C= εc 2 and ε 0 C=
There is a point which transition happens for the coefficient of friction plots and it means that after that there is no dependency on the friction of coefficient
COR
•
AL particle on Glass substrate
Contact Area um^2
Study on Coefficient of Friction:
properties of substrate (Sapphire )* Elastic Modulus 416 GPa Poisson’s ratio 0.231 Density 3980 kg/m3 Specific heat 755 J/Kg K 33 W/m K Thermal conductivity Thermal expansion coefficient 4.6 e-6 K-1
B, MPa 154.3
• •
V = 530 m/s
0.05
A, MPa 270
•
V = 416 m/s
0.2
• Plastic behavior: Bilinear Johnson-Cook flow stress model
•
V = 530 m/s
0.25
3D model Dynamic explicit Analysis Particle size: 20-30 μm Impact velocity: 100-800 m/s Initial Temperature: 293K Friction coefficient: 0.3 Fully coupled, thermal-stress analysis Element removal and nodal erosion technique • Material Properties:
𝜎 = 𝐴 + 𝐵𝜀𝑝𝑛
V = 416 m/s
Coefficient of Restitution and Diameter change as a function of Initial impact velocity:
• • • • • • • •
𝑇 − 𝑇𝑅 1− 𝑇𝑚 − 𝑇𝑅
V = 286 m/s
•
Method
𝜀𝑝· 1 + 𝐶log · 𝜀0
V = 175 m/s
•
Nature of the impact • Large deformations • Very short impact durations (10–1000 ns) • High strain-rates (> 1e4 1/s)
𝑚
V = 286 m/s
V = 699 m/s
Scraping test is designed to measure the bonding strength between two surfaces in contact. It helps to study the cohesion between the particle and substrate.
Bilinear JC
V = 175 m/s
V = 663 m/s
High velocity impact of micron-scale particles results in: • polishing of the surface (10-30 m/s) • shot peening (20-150 m/s) • material erosion from the surface (100-500 m/s) • Cold Spray: deposition of particle onto the surface (300-1200 m/s)
properties of particle (AL)* Elastic Modulus 68.9 Gpa Poisson’s ratio 0.33 Density 2700 kg/m3 Specific heat 896 J/Kg K Thermal conductivity 167 W/m K Thermal expansion coefficient 23.6e-6 K-1 Inelastic heat fraction 0.9
Experiments
Classic JC
COR
Bonding strength:
Deformation of particles on a hard substrate:
Background
Results: Particle bonding strength
3.9 3.8 3.7 R² = 0.9692
COR Contact Area
3.6 3.5
Poly. (COR) Poly. (Contact Area)
0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
COF
3.4
Acknowledgements • Funding for this work from the US Army under Grant Number W911NF-15-2-0026 is gratefully acknowledged. • The authors would like to gratefully acknowledge Professor Jae-Hwang Lee, University of Massachusetts, Amherst , who provided the single particle impact tests data. • The authors would like to gratefully acknowledge Professor Christian Widner and Mr Ozan Ozdemir, South Dakota School of Mines & Technology, who provided the cold-sprayed material samples.
Impact Mechanics of Micron Scale Metal Particles Carried by a Supersonic Jet Results: Impact with a hard substrate
Abstract • This work is motivated by the Cold Spray technology which is currently used to deposit thick metal coatings, with the potential to achieve 3D-printed, load bearing components. • We report the deformation characteristic of micron scale (~20 µm) metal (Al-6061) particles in high velocity impacts (102-103 m/s) with hard (sapphire) and deformable (Al6061) surfaces. • The particles rebound from the hard substrate but bond with the metal substrate if the conditions are “right.” • Under these conditions the material experiences strain rates (107 – 108) causing severe plastic deformation. It is well known that under such high strain rates, the flow (yield) stress of the material increases. • Experiments conducted by collaborators and theoretical analysis by FEM were used to investigate the impact mechanics. • It was shown that a bilinear JC-model is suitable to predict the deformation characteristics of a single particle, impacting a zirconium surface at room temperature. • Scraping tests of aluminum particles impacting the deformable substrate showed that particles tend to shear off in the middle, rather than the substrate-particle interface. • Results of this ongoing work are useful in uncovering the fundamental mechanics of particle bonding in the Cold Spray technology.
V = 663 m/s
• Experiments and simulations shows that the particles does not separate from the substrate, however, they are breaking due to the shear forces. • Peak values of the horizontal reaction force in both experiments and simulations are on the same order of magnitude and they are around 0.128 N
V = 699 m/s
In bilinear Johnson-Cook Model, as the plastic strain rate increases, the yield stress of the material rises more. Consequently, the material behaves harder and deforms less. That’s why they look very similar to experiments. The Classic Johnson-Cook model, cannot predict dynamic behavior of material precisely, in high strain rate phenomena (more than 1e4 /s)
Conclusions • Bilinear JC model is an appropriate model to anticipate the mechanical behavior of a dynamic impact problem, especially in Cold Spray applications. • In debonding simulations and experiments, it is observed that the interface strength of the bonding is stronger than yield strength of the material. • Simulations show that the COF has almost no effect on any of the metrics, regardless of the impact velocity.
Vr/Vi
0.15 0.1
0 0
200
400
Vi, m/s
600
800
References
JC-4 [2]
0.2215 0.002
JC-5 [1]
270
138.2
0.1792 0.002
𝒏
𝑪𝑪
C2
if ε p < εc if ε p > εc 𝜺̇ 𝒄
0.1301
𝒎
1.34
𝑻𝒎 , K 925
597.2
0.1301
1.34
925
597.2
A,B,n,C,m are the JC material parameters measured at or below the transition temperature T,TR,Tm are the current temperature, Room temperature and melting temperature is the equivalent plastic strain rate 𝜀𝑝· is the reference strain rate 𝜀0·
* All material properties are temperature dependent, however, properties in the room temperature are just reported here.
•
•
This transition occurs fast in soft substrate and has some delay in hard substrate. In general, CoF locks the amount of particle spreading on the substrate and helps to achieve more realistic results.
µ = 0.05
µ = 0.5
0.07
µ = 0.8
Al-Glass, 699 m/s, 23.4 um
0.06
R² = 0.9057
0.05 0.04 0.03
R² = 0.9993
0.02
COR
0.01
Poly. (COR)
0
Contact Area Poly. (Contact Area)
180 160 140 120 100 80 60 40 20 0
[1] Manes, A., et al. (2011). Analysis of strain rate behavior of an Al 6061 T6 alloy. Procedia Engineering, 10, 3477-3482. [2] Manes, A., et al. (2013). An experimental–numerical investigation on aluminum tubes subjected to ballistic impact with soft core 7.62 ball projectiles. Thin-Walled Structures 73 6880. [3] Lesuer, D. et al. (1999). Modeling large strain, high rate deformation in metals. Engineering Research, Development and Technology. [4] Manes, A., et al. (2011). Analysis of strain rate behavior of an Al 6061 T6 alloy. Procedia Engineering, 10, 3477-3482. [5] Dina Goldbaum, J. Michael Shockley, Richard R. Chromik, Ahmad Rezaeian, Stephen Yue, Jean-Gabriel Legoux, and Eric Irissou. “The Effect of Deposition Conditions on Adhesion Strength of Ti and Ti6Al4V Cold Spray Splats”Journal of thermal spray technology(2011)
0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
COF
AL particle on AL substrate µ = 0.05
µ = 0.5
µ = 0.8
0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0
Al-Al, 699 m/s, 23.4 um R² = 0.9977
4.1 4
Contact Area um^2
1 C= 1 and ε 0 C= εc 2 and ε 0 C=
There is a point which transition happens for the coefficient of friction plots and it means that after that there is no dependency on the friction of coefficient
COR
•
AL particle on Glass substrate
Contact Area um^2
Study on Coefficient of Friction:
properties of substrate (Sapphire )* Elastic Modulus 416 GPa Poisson’s ratio 0.231 Density 3980 kg/m3 Specific heat 755 J/Kg K 33 W/m K Thermal conductivity Thermal expansion coefficient 4.6 e-6 K-1
B, MPa 154.3
• •
V = 530 m/s
0.05
A, MPa 270
•
V = 416 m/s
0.2
• Plastic behavior: Bilinear Johnson-Cook flow stress model
•
V = 530 m/s
0.25
3D model Dynamic explicit Analysis Particle size: 20-30 μm Impact velocity: 100-800 m/s Initial Temperature: 293K Friction coefficient: 0.3 Fully coupled, thermal-stress analysis Element removal and nodal erosion technique • Material Properties:
𝜎 = 𝐴 + 𝐵𝜀𝑝𝑛
V = 416 m/s
Coefficient of Restitution and Diameter change as a function of Initial impact velocity:
• • • • • • • •
𝑇 − 𝑇𝑅 1− 𝑇𝑚 − 𝑇𝑅
V = 286 m/s
•
Method
𝜀𝑝· 1 + 𝐶log · 𝜀0
V = 175 m/s
•
Nature of the impact • Large deformations • Very short impact durations (10–1000 ns) • High strain-rates (> 1e4 1/s)
𝑚
V = 286 m/s
V = 699 m/s
Scraping test is designed to measure the bonding strength between two surfaces in contact. It helps to study the cohesion between the particle and substrate.
Bilinear JC
V = 175 m/s
V = 663 m/s
High velocity impact of micron-scale particles results in: • polishing of the surface (10-30 m/s) • shot peening (20-150 m/s) • material erosion from the surface (100-500 m/s) • Cold Spray: deposition of particle onto the surface (300-1200 m/s)
properties of particle (AL)* Elastic Modulus 68.9 Gpa Poisson’s ratio 0.33 Density 2700 kg/m3 Specific heat 896 J/Kg K Thermal conductivity 167 W/m K Thermal expansion coefficient 23.6e-6 K-1 Inelastic heat fraction 0.9
Experiments
Classic JC
COR
Bonding strength:
Deformation of particles on a hard substrate:
Background
Results: Particle bonding strength
3.9 3.8 3.7 R² = 0.9692
COR Contact Area
3.6 3.5
Poly. (COR) Poly. (Contact Area)
0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
COF
3.4
Acknowledgements • Funding for this work from the US Army under Grant Number W911NF-15-2-0026 is gratefully acknowledged. • The authors would like to gratefully acknowledge Professor Jae-Hwang Lee, University of Massachusetts, Amherst , who provided the single particle impact tests data. • The authors would like to gratefully acknowledge Professor Christian Widner and Mr Ozan Ozdemir, South Dakota School of Mines & Technology, who provided the cold-sprayed material samples.
