Microstructural variations and machining characteristics of silicon nitride ceramics from increasing the temperature in laser assisted machining

Lee, Su-Jin; Kim, Jong-Do; Suh, Jeong

doi:10.1007/s12541-014-0466-y

Cited by 37 publications

(10 citation statements)

References 8 publications

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“…It can be seen from the SEM images of the machined surface shown in Figure 3 that when the laser power is 225 W, the porous structure formed by the burst of nitrogen bubbles under the surface indicates the oxidation of the surface. This conclusion is consistent with the study of the oxidation mechanism of Si3N4 by Lee et al [7]. When the laser power is 195 W, 100 W, and 40 W, the machined surfaces are not porous.…”

Section: Microstructural Observations and Eds Analysissupporting

confidence: 92%

“…The root cause is that machining is done in the brittle region, not in the plastic region. Extensive experiments conducted on various ceramics, such as Si 3 N 4 [3][4][5][6][7][8][9], aluminum oxide (Al 2 O 3 ) [10,11], zirconia (ZrO 2 ) [12], and other ceramic composite materials [13][14][15][16][17], have proven that laser-assisted machining (LAM) is an effective method to solve the above problems. The high-power laser beam focused on the surface of the ceramic material can heat the material to a very high temperature in a short time before the material is cut, soften the material, reduce the yield strength to below the fracture strength, and then change the cutting performance of the material.…”

Section: Introductionmentioning

confidence: 99%

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A Study on Work Hardening in the Laser-Assisted Machining of Si3N4 Ceramics under Different Material Removal Modes

Zhao

et al. 2020

Metals

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In order to understand the work hardening phenomenon and mechanism of laser-assisted machining (LAM) of Si3N4 ceramics, the work hardening degree of LAM Si3N4 under different material removal modes was studied. Two sets of single-factor experiments were performed in which the laser power and the cutting depth were changed respectively. The results show that work hardening is the result of the combination of heat and cutting deformation during cutting. The work hardening degree decreases with the increase of material softening degree. When the material is removed plastically, the work hardening degree is 110–115%.

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Section: Microstructural Observations and Eds Analysissupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

A Study on Work Hardening in the Laser-Assisted Machining of Si3N4 Ceramics under Different Material Removal Modes

Zhao

et al. 2020

Metals

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“…The surface of the Si 3 N 4 workpiece was oxidized to form an amorphous silicate, which could reduce the hardness and, finally, promote the material removal rate and benefit the tool wear. 8 However, these above studies mostly focused on the reduction of machined surface roughness, forces and removal mechanism. Studies on new process controls to minimize subsurface damage are rare.…”

Section: Introductionmentioning

confidence: 99%

Laser-assisted grinding of reaction-bonded SiC

Luo

Chang

et al. 2020

Journal of Micromanufacturing

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The article presents the development of a novel laser-assisted grinding (LAG) process to reduce surface roughness and subsurface damage in grinding reaction-bonded silicon carbide (RB-SiC). A thermal control approach is proposed to facilitate the process development, in which a two-temperature model (TTM) is applied to control the required laser power to thermal softening of RB-SiC prior to the grinding operation without melting the workpiece or leaving undesirable microstructural alteration. Fourier’s law is adopted to obtain the thermal gradient for verification. An experimental comparison of conventional grinding and LAG shows significant reduction of machined surface roughness (37%–40%) and depth of subsurface damage layer (22%–50.6%) using the thermal control approach under the same grinding conditions. It also shows high specific grinding energy 1.5 times that in conventional grinding at the same depth of cut, which accounts for the reduction of subsurface damage as it provides enough energy to promote ductile-regime material removal.

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“…The study showed that the Ti-6Al-4V alloy has high mechanical characteristics and is biologically compatible with the human body. Lee et al [7] studied LAM of silicon nitride ceramics. Ceramics are widely used in many industries, such as engines, medical applications, aerospace, and ocean fields.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Thermal Effect by Multi Heat Sources and Machining Characteristics of Laser and Induction Assisted Milling

Lee

2019

Materials

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Thermally assisted machining (TAM) is an effective method for difficult-to-cut materials, and works by locally preheating the workpiece using various heat sources, such as laser, induction, and plasma. Recently, many researchers have studied TAM because of its low manufacturing costs, high productivity, and quality of materials. Laser assisted machining (LAM) has been studied by many researchers, but studies on TAM using induction or plasma heat sources, which are much cheaper than lasers, have been carried out by only a few researchers. Lasers have an excellent preheating effect, but are expensive, and the temperature of the heated workpiece drops quickly. Here, multi heat sources were used to solve the shortage in supplied heat source with a single heat source. Induction was applied as an additional heat source. The purpose of this study is to analyze the thermal effect and temperature distribution of single heat source and multi heat sources, and compare the machining characteristics according to heat source types. In order to analyze the preheating effect according to the feed rate of the heat sources, a temperature measurement experiment using thermocouples was carried out, and the efficiency of the thermal effect using multi heat sources was verified. In addition, the effectiveness of the thermal analysis results was verified by comparison with the measured temperature distribution. The machining characteristics of Inconel 718 and Ti-6Al-4V with laser, induction, and laser-induction assisted milling (LIAMill) were analyzed, by cutting force and surface roughness.

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Microstructural variations and machining characteristics of silicon nitride ceramics from increasing the temperature in laser assisted machining

Cited by 37 publications

References 8 publications

A Study on Work Hardening in the Laser-Assisted Machining of Si3N4 Ceramics under Different Material Removal Modes

A Study on Work Hardening in the Laser-Assisted Machining of Si3N4 Ceramics under Different Material Removal Modes

Laser-assisted grinding of reaction-bonded SiC

A Study on the Thermal Effect by Multi Heat Sources and Machining Characteristics of Laser and Induction Assisted Milling

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