Erosion-corrosion of Ti-6Al-4V in elevated temperature air environment

Zhou, Jianren; Bahadur, S.

doi:10.1016/0043-1648(95)07161-x

Cited by 31 publications

(15 citation statements)

References 6 publications

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“…Table 7.3 shows that the cross-sectional areas of these channels decreased as the initial particle embedding area coverage increased, confirming that particle embedding did indeed shield the substrate from the incoming particles. The result in agreement with the suggestion of Lathabai et al [14] and Zhou and Bahadur [72] that embedded particles may confer a shielding effect. The use of LN 2 reduced the amount of embedded particles in the three materials significantly, with a confidence level of 99%.…”

Section: Particle Embedding In Pmma (A) Removal Of Embedded Particlessupporting

confidence: 93%

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Abrasive Jet Micro-Machining of Polymeric Materials

Hailu¹

2023

Preprint

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In the abrasive jet micro-machining (AJM) process, a jet of small particles is directed through an erosion resistant mask opening so that micro-sized features (i.e., micro-channels, holes, etc.) can be machined for the fabrication of micro-devices such as micro-fluidic and micro-electro-mechanical-systems (MEMS). Polymeric materials and elastomers have found applications in a wide variety of micro-devices. This thesis investigates the AJM of such materials, addressing the major challenges that must be overcome in order for the process to gain wider acceptance in industry. The thesis first presents a novel cryogenically assisted abrasive jet micro-machining (CAJM) technique that enables the micro-machining of elastomers such as polydimethylsiloxane (PDMS) that cannot be machined at room temperature. It was found that the erosion rate during CAJM is greatly increased, and the degree of particle embedment greatly decreased, compared to room temperature experiments. A finite element (FE) analysis was used to investigate the relationships between erosion, the heat transfer of the cooling jet and the resulting target temperature during the CAJM of channels in PDMS. The analysis illustrated the asymmetric nature of the cooling with much more cooling occurring towards the trailing edge of the jet. It was found that the predicted shape of the evolving machined surface profiles was improved significantly when a FE model was used to account for thermal distortion occurring during the CAJM process. An unwanted consequence of the AJM of polymeric materials was found to be particle embedding. Criteria leading to the embedding of spherical and angular particles in such materials were identified and modelled using rigid plastic analyses. It was found that the likelihood of embedding was proportional to the static coefficient of friction between the particle and the target for angular particles, and the depth of penetration for spherical particles. Scanning electron microscopy with EDX was used to measure the area coverage of embedded Al2O3 particles in polymers and elastomers, in order to evaluate various cleaning methods that were developed. It was found that glass bead blasting at 45˚ followed by the freezing technique was the best method to remove embedded particles, leading to 100% removal in some cases.

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Section: Particle Embedding In Pmma (A) Removal Of Embedded Particlessupporting

confidence: 93%

“…In machining operations particle embedding may reduce the efficiency of chip removal. For example, Zhou and Bahadur [72] reported that embedded silicon carbide particles may have prevented the removal of a chip from a Ti-6Al-4V substrate by blocking the cutting action of an impacting particle.…”

Section: Particle Embedding During Solid Particle Erosionmentioning

confidence: 99%

Abrasive Jet Micro-Machining of Polymeric Materials

Hailu¹

2023

Preprint

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“…Hence, it is concluded that Ti6Al4V alloy shows semi-ductile erosion behavior as mentioned in literature [9,10]. On the other hand, the erosion rates of the samples are increased with increase in particle impingement velocity.…”

Section: Resultsmentioning

confidence: 56%

Influences of Particle Impingement Angle and Velocity on Surface Roughness, Erosion Rate, and 3D Surface Morphology of Solid Particle Eroded Ti6Al4V Alloy

et al. 2014

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In this study, it is aimed to investigate the eects of particle impingement angle and velocity on the surface roughness, erosion rate, and surface morphology of solid particle eroded Ti6Al4V alloy. Ti6Al4V samples were eroded in erosion test rig under various particle impingement angles (15• and 90 • ) and impingement velocities (33 m/s, 50 m/s, and 75 m/s) by using 120 mesh garnet erodent particles. Subsequently, erosion rates and surface roughness values of samples were analyzed and calculated as a function of particle impingement angle and velocity. Moreover, 3D surface morphologies of the eroded samples were prepared by using high definition scanner and image processing programs. Results show that erosion rates, surface roughness values and surface morphologies of Ti6Al4V alloy have been varied signicantly depending on the both particle impingement angle and velocity. Erosion rates of Ti6Al4V alloy were decreased with increases in particle impingement angle; on the other hand, the surface roughness values were increased with increases in particle impingement angle. Both erosion rates and surface roughness values were increased with increases in particle impingement velocity. Finally, the surface morphologies of the eroded samples were evaluated deeply. It is concluded that the surface morphology variation of the Ti6Al4V alloy depending on the particle impingement angle and velocity were well correlated with the erosion rates and the surface roughness values.

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“…the tendency for some particles to not rebound but instead remain buried in the material. Particle embedding can be a problem in a wide variety of applications because embedded abrasives may reduce the erosion rate [10], and for AJM in particular, negatively impact the heat transfer rate in abrasive jet micro-machined heat exchangers, and increase the roughness, thus affecting the flow in micro-machined microfluidic devices [11,12]. However, embedment of particles may also be considered as a beneficial phenomenon when more resistance against erosion is required [13,14].…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis and numerical modeling of particle embedment and fracture in the solid particle erosion of ductile materials

Hadavi¹

2021

Preprint

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Embedment and fracture of abrasives are two often neglected important phenomena that can affect material removal occurring in industrial processes that involve high speed impact of particles on relatively ductile targets. This thesis proposes new methodologies to predict the likelihood of particle embedment and fracture for a typical solid particle erosion application. Double-pulsed laser shadowgraphy was used to measure the instantaneous orientation of angular 89-363 μm SiC particles within a micro-abrasive jet, in order to assess whether their orientation affected the propensity for particle embedment. A tendency for particles to orient with the jet axis was measured and successfully modelled (<9% error), with larger abrasives more likely to orient. The measured instantaneous orientation of particles was used to generate a three-dimensional coupled finite element and smoothed particle hydrodynamics model capable of simulating the particle embedment. Use of various combinations of process parameters yielded embedment predictions that agreed with measured ones with, at most, a 16% error. Increases in particle size, orientation angle, and velocity were found to enhance the propensity for embedment. Double-pulsed laser shadowgraphy was used to record the impact and fracture of abrasives upon impact. A numerical model that utilized an Element Free Galerkin (EFG) technique with a novel scheme for generating realistic three-dimensional particle geometries was used to simulate the particle fracture. For a wide variety of process parameters, the numerical predictions of particle average size, roundness and rebound velocity agreed with the corresponding measurements to within 10%, at most. The propensity for particle fracture was found to depend on the magnitude of particle kinetic energy perpendicular to the target. It was confirmed that at the same incident velocity, larger particles were more likely to fracture. However, for the same kinetic energy, smaller particles were more likely to fracture. To the best knowledge of the author, this thesis is the first to report measurements of particle orientation and particle fracture in abrasive jets, and the first to develop numerical modeling of particle fracture and embedment. The results have important implications for erosion testing and abrasive jet machining operations.

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Erosion-corrosion of Ti-6Al-4V in elevated temperature air environment

Cited by 31 publications

References 6 publications

Abrasive Jet Micro-Machining of Polymeric Materials

Abrasive Jet Micro-Machining of Polymeric Materials

Influences of Particle Impingement Angle and Velocity on Surface Roughness, Erosion Rate, and 3D Surface Morphology of Solid Particle Eroded Ti6Al4V Alloy

Experimental analysis and numerical modeling of particle embedment and fracture in the solid particle erosion of ductile materials

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