Mechanical Behavior of Inconel 625 at Elevated Temperatures

Oliveira, Mauro Macêdo de; Couto, Antônio Augusto; Almeida, Gisele Fabiane Costa; Reis, Danieli Aparecida Pereira; Lima, Nelson Batista de; Baldan, Renato

doi:10.3390/met9030301

Cited by 61 publications

(20 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Literature studies have shown that the PLC effect occurs not only in copper, aluminum and nickel alloys [2][3][4]17,18], but also in some steel grades. Plastic instability phenomenon was observed in steels with increased Cr content [7,19], austenitic stainless steels [20], Hadfield steels [21] and dual phase (DP) steels [22].…”

Section: Introductionmentioning

confidence: 99%

“…Some of the AHSSs are also prone to plastic instability phenomenon, such as high-manganese Twinning-Induced Plasticity (TWIP) steels [8], medium-manganese steels [6,13] and Q&P steels [10]. Literature studies have shown that the PLC effect occurs not only in copper, aluminum and nickel alloys [2][3][4]17,18], but also in some steel grades. Plastic instability phenomenon was observed in steels with increased Cr content [7,19], austenitic stainless steels [20], Hadfield steels [21] and dual phase (DP) steels [22].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review

et al. 2019

View full text Add to dashboard Cite

The paper reviews the recent works concerning the Portevin-Le Chatelier (PLC) effect in Advanced High-Strength Steels (AHSSs) with a special attention to high-strength medium-manganese steels. Theories explaining the mechanism of the plastic instability phenomenon in steels with medium-and high-Mn contents were discussed. The relationships between microstructural effects such as TRIP (Transformation-Induced Plasticity), TWIP (Twinning-Induced Plasticity) and the PLC effect were characterized. The effects of processing conditions including a deformation state (hot-rolled and cold-rolled) and strain parameters (deformation temperature, strain rate) were addressed. Factors affecting the value of critical strain for the activation of serrated flow behavior in particular in medium-manganese steels were described.The explanation of the Portevin-Le Chatelier mechanism in medium-Mn steels showing the TRIP effect is a complicated issue because of their microstructure consisting of several phases, as well as the TRIP effect exhibited by these steels. The exact characteristics of the factors affecting the PLC effect in AHSS is very important, both from a research point of view and their industrial implementation. This overview concerns the PLC phenomenon in Advanced High Strength Steels (AHSSs), with particular emphasis on advanced medium-Mn TRIP steels. The Nature of PLC Effect in SteelsThe plastic instability phenomenon occurring during the deformation of metallic materials shows two most common forms of propagative bands: Lüders and Portevin-Le Chatelier bands. The Lüders bands refer to the regions of localized strain. They form immediately after the onset of plastic deformation from the yield point drop, followed to a dominant stage of the stress plateau stage. Lüders bands are commonly caused by static strain aging (SSA) [13]. Static strain aging is characterized by an increase in strength properties associated with a decrease in plasticity. The PLC bands are represented by characteristic serrations on stress-strain curves. PLC bands are usually related to the dynamic strain aging (DSA) effect. The occurrence of the PLC bands is much more erratic, and can be observed in various forms (serration types) in comparison to the Lüders bands.There are several theories which explain the PLC effect in metallic materials. However, none has been so far clearly confirmed. The first interpretation of this phenomenon was proposed by Cottrell [1]. From his point of view, the PLC effect is related to the interactions between solute atoms, such as C or N, and mobile dislocations. The presence of serrations on a tensile curve is associated with the rapid release of dislocations from the atmospheres of dissolved atoms, which block their movement. This model is based on the assumption that atmospheres are formed around dislocations due to volume diffusion. In the presence of substitution atoms, diffusion is facilitated by vacancies resulting from plastic deformation. The interstitial gaps located in the vicinity of the dislocation are enl...

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Nickel-based superalloys consist of over 50% nickel and 8-12 alloying elements added to improve their characteristics. Due to their very good performance at high temperatures and pressures, there is great demand for them in the aerospace, processing, and manufacturing industries [1]. The Nimonic 263 alloy belongs to the nickel-based superalloy group.…”

Section: Introductionmentioning

confidence: 99%

Experimental Optimization of Nimonic 263 Laser Cutting Using a Particle Swarm Approach

Šibalija

Petronić²,

Milovanović

2019

Metals

View full text Add to dashboard Cite

This paper presents an experimental study carried out on Nimonic 263 alloy sheets to determine the optimal combination of laser cutting control factors (assisted gas pressure, beam focus position, laser power, and cutting speed), with respect to multiple characteristics of the cut area. With the aim of designing laser cutting parameters that satisfy the specifications of multiple responses, an advanced multiresponse optimization methodology was used. After the processing of experimental data to develop the process measure using statistical methods, the functional relationship between cutting parameters and the process measure was determined by artificial neural networks (ANNs).Using the trained ANN model, particle swarm optimization (PSO) was employed to find the optimal values of laser cutting parameters. Since the effectiveness of PSO could be affected by its parameter tuning, the settings of PSO algorithm-specific parameters were analyzed in detail. The optimal laser cutting parameters proposed by PSO were implemented in the validation run, showing the superior cut characteristics produced by the optimized parameters and proving the efficacy of the suggested approach in practice. In particular, it is demonstrated that the quality of the Nimonic 263 cut area and the microstructure were significantly improved, as well as the mechanical characteristics.Parameters of the laser cutting process must be properly tuned in order to obtain the desired outputs. The laser power must be sufficient to enable the cutting; the cutting speed should be high enough to prevent the diffusion of heat in a material and to form a broad heat-affected zone (HAZ) [4]. The assisting gas is very important for producing a high-quality cut without a grate, since it does not permit molten material droplets' solidification onto the cut surface. The cutting speed must be balanced; if excessive speed is used the grate would remain, while, with a very low speed, the edge quality of the cut would be affected and a wide HAZ would form [5].The cutting control factors considered in this study are the assisting gas pressure, the position of the beam focus, the laser power, and the cutting speed. At the output, seven responses of the cut area are observed. Since the process is characterized by multiple parameters and responses, an advanced optimization methodology is needed to obtain the optimal cutting setting that satisfies the specifications for multiple, correlated responses. Simulated annealing (SA) and a genetic algorithm (GA) have been employed previously, and it has been demonstrated that SA outperformed GA in the proposed method [6]. Particle swarm optimization (PSO) is used in this study and benchmarked with SA in terms of the quality, i.e., the accuracy of the obtained optimum, the effects of the algorithm's parameters on the obtained optimum, and the convergence speed. Since metaheuristic algorithms must be adequately tuned to obtain the right solution, the setting of the major PSO algorithm's parameters is studied in detail to evaluate th...

show abstract

“…These creep conditions, characterized by low stresses at moderately high homologous temperatures and long creep times lead to diffusion creep [3], which is dominated by the diffusion of vacancies and most commonly leads to intergranular fracture [4,5]. In some cases, single crystals [6] are produced to mitigate this issue, although this is not feasible for large components.…”

Section: Introductionmentioning

confidence: 99%

Cavity Nucleation and Growth in Nickel-Based Alloys during Creep

2022

View full text Add to dashboard Cite

The number of fossil fueled power plants in electricity generation is still rising, making improvements to their efficiency essential. The development of new materials to withstand the higher service temperatures and pressures of newer, more efficient power plants is greatly aided by physics-based models, which can simulate the microstructural processes leading to their eventual failure. In this work, such a model is developed from classical nucleation theory and diffusion driven growth from vacancy condensation. This model predicts the shape and distribution of cavities which nucleate almost exclusively at grain boundaries during high temperature creep. Cavity radii, number density and phase fraction are validated quantitively against specimens of nickel-based alloys (617 and 625) tested at 700 °C and stresses between 160 and 185 MPa. The model’s results agree well with the experimental results. However, they fail to represent the complex interlinking of cavities which occurs in tertiary creep.

show abstract

Mechanical Behavior of Inconel 625 at Elevated Temperatures

Cited by 61 publications

References 38 publications

Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review

Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review

Experimental Optimization of Nimonic 263 Laser Cutting Using a Particle Swarm Approach

Cavity Nucleation and Growth in Nickel-Based Alloys during Creep

Contact Info

Product

Resources

About