Development of Micro Laser Powder Bed Fusion for Additive Manufacturing of Inconel 718

Shielding gas, metal vapors, and gases trapped inside powders during atomization can result in gas porosity, which is known to degrade the fatigue strength and tensile properties of components made by laser powder bed fusion additive manufacturing. Post-processing and trial-and-error adjustment of processing conditions to reduce porosity are time-consuming and expensive. Here, we combined mechanistic modeling and experimental data analysis and proposed an easy-to-use, verifiable, dimensionless gas porosity index to mitigate pore formation. The results from the mechanistic model were rigorously tested against independent experimental data. It was found that the index can accurately predict the occurrence of porosity for commonly used alloys, including stainless steel 316, Ti-6Al-4V, Inconel 718, and AlSi10Mg, with an accuracy of 92%. In addition, experimental data showed that the amount of pores increased at a higher value of the index. Among the four alloys, AlSi10Mg was found to be the most susceptible to gas porosity, for which the value of the gas porosity index can be 5 to 10 times higher than those for the other alloys. Based on the results, a gas porosity map was constructed that can be used in practice for selecting appropriate sets of process variables to mitigate gas porosity without the need for empirical testing.

Section: Methodsmentioning

confidence: 99%

“…A total of 93 sets of data on gas porosity formation for four alloys at various processing conditions were collected from the literature [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]. Among the 93 sets of data, 60 cases had gas pores and 33 cases were without experimentally detected gas pores.…”

Section: Data Collection and Analysismentioning

confidence: 99%

Mitigation of Gas Porosity in Additive Manufacturing Using Experimental Data Analysis and Mechanistic Modeling

Sinha,

Mukherjee

2024

“…A new kind of NiCoCr-based superalloy has been developed for ultra-supercritical power equipment at temperatures above 650 °C [ 1 ]. The degradation of mechanical properties and steam corrosion at high temperature put forward higher requirements for alternative alloy materials.…”

Section: Introductionmentioning

confidence: 99%

Crack Inhibition and Performance Modification of NiCoCr-Based Superalloy with Y2O3 Nanoparticles by Laser Metal Deposition

et al. 2023

A new precipitation strengthening NiCoCr-based superalloy with favorable mechanical performance and corrosion resistance was designed for ultra-supercritical power generation equipment. The degradation of mechanical properties and steam corrosion at high temperatures put forward higher requirements for alternative alloy materials; however, when the superalloy is processed to form complex shaped components through advanced additive manufacturing techniques such as laser metal deposition (LMD), hot cracks are prone to appear. This study proposed that microcracks in LMD alloys could be alleviated with powder decorated by Y2O3 nanoparticles. The results show that adding 0.5 wt.% Y2O3 can refine grains significantly. The increase in grain boundaries makes the residual thermal stress more uniform to reduces the risk of hot cracking. In addition, the addition of Y2O3 nanoparticles enhanced the ultimate tensile strength of the superalloy at room temperature by 18.3% compared to original superalloy. The corrosion resistance was also improved with 0.5 wt.% Y2O3, which was attributed to the reduction of defects and the addition of inert nanoparticles.

“…Khademzadeh et al [ 4 ] developed a micro-laser powder bed fusion for the additive manufacturing of Inconel 718 alloy. They optimized the process parameters of the additive manufacturing machine to obtain the best microstructural properties for post-printing heat-treated Inconel 718.…”

mentioning

confidence: 99%

Investigation of the Microstructural and Corrosion Properties of Steels and Light Alloys

Pezzato,

Gennari

2023

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