Investigation of Agglomerated and Porous Ceramic Powders Suitable for Cold Spray

2021 ◽  
Author(s):  
Geoffrey Celeste ◽  
Vincent Guipont ◽  
Djamel Missoum-Benziane
Keyword(s):  
Cold Spray ◽  
Porous Ceramic ◽  
Ceramic Materials ◽  
Deposition Process ◽  
Impact Behavior ◽  
Ceramic Powders ◽  
Crystallite Sizes ◽  
Cold Gas Spraying ◽  
The Impact

Abstract Cold gas spraying is a solid-state deposition process developed for metallic powders as feedstock materials. For ceramic materials; such low temperature-high velocity kinetic process is still questionable but could have interesting advantages. In the CERASOL project (ANR-19-CE08-0009); the nature and the architecture of porous ceramic powders involving agglomerated sub-micrometric grains are investigated. To that purpose; three oxide ceramics powders (alumina; zirconia and yttria) have been prepared for cold spray. These powders were analyzed in order to assess their architecture (composition; particle size; porosity; density; crystallite sizes…). Preliminary cold spray experiments were carried out implementing velocities measurements for various stand-off distances and spraying of coupons with line experiments. The characteristics of the deposited layers have been examined by SEM and XRD in order to discuss the role of the powder architecture on the impact behavior of the nanostructured agglomerated particles. The role of the gas stream that affects the kinetic and the trajectory of the particles are also discussed.

Numerical Simulation of the Cold Spray Deposition Process for Aluminium and Copper

2012 ◽  
Author(s):  
Jing Xie ◽  
Daniel Nelias ◽  
Hélène Walter-le Berre ◽  
Yuji Ichikawa ◽  
Kazuhiro Ogawa
Keyword(s):  
Reference Frame ◽  
Cold Spray ◽  
High Speed ◽  
Gas Flow ◽  
Heat Dissipation ◽  
Spray Deposition ◽  
Deposition Process ◽  
Arbitrary Lagrangian Eulerian ◽  
Systematic Analysis ◽  
The Impact

Cold spray is a rapidly developing coating technology for depositing materials in the solid state. In this deposition process, the spray particles are accelerated to a high velocity by a high-speed gas flow, and then form a dense and high quality coating due to plastic deformation of particles impinged upon the solid surface of substrate. 2D and 3D modelling of particle impacting behaviours in cold spray deposition process by using ABAQUS/Explicit was conducted for four couples of materials (i.e. impacting particle/impacted substrate): copper/aluminium, aluminium/copper, copper/copper, and aluminium/aluminium. A systematic analysis of a single impact was carried out considering different parameters, such as the initial impact velocity, initial temperature and contact angle, which affect the deposition process and subsequently the mechanical properties of coating. Three numerical methods have been evaluated and their performances are discussed for various simulation settings: (i) modelling in a Lagrangian reference frame; (ii) modelling using adaptive remeshing in an Arbitrary Lagrangian Eulerian (ALE) reference frame; and (iii), modelling in a CEL reference frame. It is found that the Coupled Eulerian Lagrangian (CEL) method has more advantages to simulate the large deformation of materials, and is also more efficient to prevent the excessive distortion of the mesh. A comparison between simulation results and experimental data from the literature was performed. Nevertheless, the CEL method is implicitly isothermal for ABAQUS v6.10, whereas the modelling in the classical Lagrangian reference frame does include coupled thermo-mechanical effects with a local increase of the temperature near the interface — due to friction — and for the highly plastically deformed elements — due to the heat dissipation linked to plasticity. A local rise of temperature at the impact surface may also be observed for oblique impacts. Finally a first attempt to simulate the deposition of several particles is made with a 3D CEL model, resulting in the creation of porosity at the interface between particles.

On Simulation of Multi-Particle Impact Interactions in the Cold Spray Process

2012 ◽  
Author(s):  
Baran Yıldırım ◽  
Andrew Hulton ◽  
Seyed Ali Alavian ◽  
Teiichi Ando ◽  
Andrew Gouldstone ◽  
...  
Keyword(s):  
Cold Spray ◽  
Failure Criteria ◽  
Material Behavior ◽  
Impact Behavior ◽  
Strength Parameter ◽  
Cold Spray Process ◽  
Spray Process ◽  
Method Effects ◽  
Cohesion Degree ◽  
The Impact

The cold spray process consists of coating build-up by sequential impact, deformation and bonding of many particles. Therefore, formation and properties of a deposited layer are not only affected by the impact behavior of a single particle, but also by subsequent impact events. To investigate the material behavior under such conditions, impact of multiple particles in cold spray was studied here by the finite element method. Effects of high strain rates and temperature on material yield and failure criteria were considered. Particle conditions prior to impact were derived from fluid dynamics calculations. To predict sticking behavior of the particle, an interfacial cohesive strength parameter was defined between the particle and the substrate. The effects of temperature and particle positioning were examined for three particle impacts. In addition, simulations involving 100 consecutive particle impacts were carried out, and findings were compared with experimental observations. Results showed that subsequent impacts have a large effect on the previously impacted particles for cohesion, degree of deformation, and residual stresses.

On the role of slip–twin interactions on the impact behavior of high-manganese austenitic steels

2014 ◽  
Vol 593 ◽  
pp. 120-126 ◽  
Author(s):  
S.M. Toker ◽  
D. Canadinc ◽  
A. Taube ◽  
G. Gerstein ◽  
H.J. Maier
Keyword(s):  
Austenitic Steels ◽  
Impact Behavior ◽  
High Manganese ◽  
The Impact

scholarly journals Size Effects of Brittle Particles in Aerosol Deposition—Molecular Dynamics Simulation

2021 ◽  
Vol 30 (3) ◽  
pp. 503-522 ◽  
Author(s):  
Bahman Daneshian ◽  
Frank Gaertner ◽  
Hamid Assadi ◽  
Daniel Hoeche ◽  
Wolfgang Weber ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Inelastic Deformation ◽  
High Speed ◽  
Aerosol Deposition ◽  
Heat Diffusion ◽  
Dynamics Simulation ◽  
Impact Behavior ◽  
High Speed Impact ◽  
The Impact

AbstractUp to now, the role of particle sizes on the impact behavior of ceramic particles in aerosol deposition not yet fully understood. Hence, with the aim to supply a more general understanding, modeling series of low strain rate compression and high-speed impact were performed by molecular dynamics on single-crystalline particles in sizes of 10-300 nm that are tuned to match mechanical properties of TiO2-anatase. The modeling results reveal that particles with original diameter of 25-75 nm exhibit three different impact behaviors that could be distinguished as (i) rebounding, (ii) bonding and (iii) fragmentation, depending on their initial impact velocity. In contrast, particles larger than 75 nm do not exhibit the bonding behavior. Detailed stress and strain field distributions reveal that combination of “localized inelastic deformation” along the slip systems and “shear localization” cause bonding of the small and large particles to the substrate. The analyses of associated temperature rise by the inelastic deformation revealed that heat diffusion at these small scales depend on size. Whereas small particles could reach a rather homogeneous temperature distribution, the evolved heat in the larger ones keeps rather localized to areas of highest deformation and may support deformation and the formation of dense layers in aerosol deposition.

The role of alloying additives and aging treatment on the impact behavior of 319 cast alloy

2011 ◽  
Vol 32 (6) ◽  
pp. 3205-3220 ◽  
Author(s):  
O. Elsebaie ◽  
A.M.A. Mohamed ◽  
A.M. Samuel ◽  
F.H. Samuel ◽  
A.M.A. Al-Ahmari
Keyword(s):  
Cast Alloy ◽  
Aging Treatment ◽  
Impact Behavior ◽  
Alloying Additives ◽  
The Impact

scholarly journals Effect of Thermal Exposure Simulating Vapor Deposition on the Impact Behavior of Additively Manufactured AlSi10Mg Alloy

2021 ◽  
Author(s):  
L. Lattanzi ◽  
M. Merlin ◽  
A. Fortini ◽  
A. Morri ◽  
G. L. Garagnani
Keyword(s):  
Impact Toughness ◽  
Vapor Deposition ◽  
Solution Treatment ◽  
Thermal Exposure ◽  
Deposition Process ◽  
Age Hardening ◽  
Impact Behavior ◽  
Innovative Solution ◽  
High Impact Strength ◽  
The Impact

AbstractThe present work focuses on the evolution of hardness and impact toughness after thermal exposure at high temperatures of the AlSi10Mg alloy produced by selective laser melting. The thermal exposure simulated the vapor deposition of coatings on aluminum alloys. The aim is to assess the possibility of combining the ageing step of heat treatments and the deposition treatment. The alloy was aged at 160 and 180 °C for up to 4 hours, both directly and after an innovative rapid solution treatment. Direct ageing had no significant effects on the microstructure, showing an almost constant hardness trend. These results accord with the impact properties, which showed a negligible difference in the impact toughness of the direct aged and the as-built samples. The same ageing treatments performed after rapid solution treatment induced age hardening in the alloy. The hardness values were lower by 38% than those of the directly aged samples. The innovative solution treatment positively affected impact toughness, which increased by 185% compared to the directly aged material. These results highlight that the ageing step can be integrated with the vapor deposition process. Moreover, the heat treatment is suitable for components requiring high impact strength after coating.

Effect of machining residual stresses on the repetitive impact behavior of silicon nitride

1995 ◽  
Vol 10 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Sreeram Srinivasan ◽  
Peter J. Blau ◽  
Julia L. Bjerke
Keyword(s):  
Silicon Nitride ◽  
Residual Stresses ◽  
Internal Combustion Engines ◽  
Wear Behavior ◽  
Ceramic Materials ◽  
Impact Behavior ◽  
Combustion Engines ◽  
Silicon Nitride Ceramic ◽  
Repetitive Impact ◽  
The Impact

Silicon nitride is a candidate valve material for internal combustion engines. Its low density and attractive mechanical properties relative to conventional metallic alloys portend significant improvements in valve performance. The production of valves involves a significant amount of machining, especially grinding. Grinding of ceramic materials may result in surface and subsurface damage in the form of fracture or residual stresses which may affect impact behavior and, consequently, the behavior of silicon nitride ceramic materials as valves. The effects of residual stresses due to grinding on the impact wear behavior of one silicon nitride composition ground under various conditions have been investigated.

Relationship between Micro-/Nano-Structure and Stress Development in TM-Doped Mg-Based Alloys Absorbing Hydrogen

2012 ◽  
Vol 194 ◽  
pp. 237-244 ◽  
Author(s):  
N.E. Skryabina ◽  
Vladimir M. Pinyugzhanin ◽  
Daniel Fruchart
Keyword(s):  
Hydrogen Absorption ◽  
Mechanical Parameters ◽  
Systematic Analysis ◽  
Nano Structure ◽  
Early Transition Metal ◽  
Crystallite Sizes ◽  
External Stresses ◽  
The Impact ◽  
Kinetics Of

In the most recent years, MgH2has attracted considerable attention for reversible hydrogen storage purposes because of a large 7.6 w% H-uptake, single plateau reaction at low pressure and abundance of metal. If the Mg ↔ H reactions take place at rather high temperature (> 300°C), the kinetic remains very low. However, early transition metal based additives (Ti, V, Nb...) improve dramatically the kinetics of hydrogen absorption/desorption, while having no essential impact on the reversible sorption capacity. Systematic analysis of many experimental data led to question chemical, physical, mechanical... parameters contributing significantly to improve the kinetics of absorption/desorption. Besides, results of theoretical and numerical computation enlighten the impact of structural and mechanical parameters owing to the local bonds of Mg/MgH2with of TM elements, in terms of total energy and electronic structure. More specifically, we found highly relevant to consider 1 - the impact of the crystallite sizes of Mg and the TM-phase, 2 - the role of internal and external stresses, as well as 3 - the role of texture on the kinetics of hydrogen absorption/desorption. Apart the previous considerations, we like to underline the role of specific TM in trapping intermediately hydrogen thus forming TMHxprior initiating the Mg ↔ MgH2nucleation process.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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