Effect of laser heat input on the properties of cladding layer

The tailoring of mechanical and technological properties of the initial material in sheet metal forming has been widely investigated and successfully applied. The benefits of such an approach can be found in the improvement of both the post-forming performances of the manufactured component and the forming process capabilities. Different strategies can be found and most of them involve a microstructural alteration by a selective heat source (e.g. laser, induction, UV light). The use of aluminium alloys combined with these strategies has been extensively investigated, while magnesium alloys are almost not yet considered from this viewpoint. In this work, we investigated the effect of a selective laser heat treatment on an AZ31 magnesium alloy sheet. After laser heat treating a single track in the centre of a blank with different heat input values, bulge tests at elevated temperatures were conducted. The dome height evolution was continuously acquired during the tests and differences between the untreated specimen and the laser treated ones have been characterized. The effect of the laser treatment was evaluated also in terms of thickness distribution of the formed specimens. A thickness discontinuity was found along the treated specimens in the transition zone between the treated and the untreated material. Results highlighted that an effective change in the forming behaviour can be induced in the treated zone depending on the laser heat input. It has thus been shown that this approach can be employed for tailoring the magnesium alloy blank properties prior to the gas forming at elevated temperatures.

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Laser Repair Cladding of K418 Ni-Base Superalloy by CoCrNiW Powder

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.1417 ◽

2011 ◽

Vol 291-294 ◽

pp. 1417-1420

Author(s):

Chang Jun Chen ◽

Qin Cao ◽

Min Zhang ◽

Qing Ming Chang ◽

Shi Chang Zhang

Keyword(s):

Electron Microscope ◽

Optimum Condition ◽

Heat Input ◽

Optical Microscope ◽

X Ray ◽

Cladding Layer ◽

Metallurgical Bonding ◽

Base Superalloy ◽

Scanning Electron ◽

Characteristic Microstructure

Laser cladding has been taken into consideration for repairing K418 Ni-based superalloy material with CoCrNiW powder.Composition of cladding materials was revealed by energy dispersive X-ray spectrum(EDS). The characteristic microstructure of the cladding layer and interface were investigated by using an optical microscope and scanning electron microscope(SEM).Cladding coatings were obtained for different process parameters, and a detailed study of the effects of these parameters has been carried out by SEM. Metallurgical bonding between the cladding layer and substrate materials was obtained.Effect of heat input on cladding cracking susceptibility has been studied to obtain optimum condition for crack-free welds. Variations in cracking susceptibility as a function of heat input is discussed with reference to metallurgical characteristics of the clads. The corresponding microstructure induced by different heat input was discussed in this paper too.

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Surface hardening characteristics of press die cast iron and plastic mold steel according to laser heat input

Modern Physics Letters B ◽

10.1142/s0217984920400291 ◽

2020 ◽

Vol 34 (07n09) ◽

pp. 2040029

Author(s):

Moo-Keun Song ◽

Jong-Do Kim

Keyword(s):

Heat Treatment ◽

Cast Iron ◽

Heat Input ◽

Surface Hardening ◽

Surface Heat ◽

Mold Material ◽

Laser Heat ◽

Die Cast ◽

Laser Heat Source ◽

Plastic Mold

In this study, the surface heat treatment of mold materials was performed using a high-power laser heat source and surface hardening characteristics were investigated. Laser surface heat treatment is a hardening method in which a surface is heated using high-density energy and self-quenched through rapid cooling. Hence, the heat input during laser heat treatment is important. The heat input for the surface hardening of each material was compared, and it was found that the heat input for each mold material was different. Additionally, die cast iron has higher thermal conductivity compared to mold steel, resulting in a larger heat input during heat treatment.

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Effects of High-Power Laser Heat Input on the Mechanical Properties of GPa-Grade Advanced High Strength TRIP Steel

Journal of Welding and Joining ◽

10.5781/jwj.2021.39.5.6 ◽

2021 ◽

Author(s):

Sangwoo Nam ◽

Hyung Won Lee ◽

Cheolhee Kim ◽

Chul-Young Jung ◽

Yonung-Min KIm

Keyword(s):

Mechanical Properties ◽

High Power ◽

Heat Input ◽

Trip Steel ◽

High Strength ◽

High Power Laser ◽

Power Laser ◽

Laser Heat

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Microstructure and Elements Concentration of Inconel 713LC during Laser Powder Bed Fusion through a Modified Cellular Automaton Model

Crystals ◽

10.3390/cryst11091065 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1065

Author(s):

Amir Reza Ansari Dezfoli ◽

Yu-Lung Lo ◽

M. Mohsin Raza

Keyword(s):

Cellular Automaton ◽

Heat Input ◽

Solid Phase ◽

Cellular Automaton Model ◽

Solute Diffusion ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Laser Heat ◽

Solidification Speed

In this study, a hybrid finite element (FE) and cellular automaton (CA) model is developed to explore crystallization behavior and alloying of Inconel713LC during Laser powder bed fusion. A cellular automaton model is considering the surface nucleation, equiaxed bulk nucleation, and grain growth kinetics. In addition, the equation for solute diffusion is coupled with a cellular automaton model to simulate the IN713LC elements segregation. During the phase change, the non-equilibrium segregation model is applied to insert the effect of ultra-fast solidification happening during LPBF. It is found that, during LPBF processing of IN713LC, the micro segregation of Nb, Ti, and C is accrued at the grain boundaries. It is further shown that the micro segregation intensity depends on the solidification speed, which is determined in turn by the laser heat input. In particular, a lower laser heat input increases the solidification speed and results in a more uniform solid phase, thereby reducing the risk of crack formation. Finally, using a comparison between simulation results and experimental observation, it was shown that the proposed model successfully predicts the bulk element concentration of IN713LC after laser melting.

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