Densification behaviour and the effect of heat treatment on microstructure, and mechanical properties of sintered nickel-based alloys

Kekana, Neo; Shongwe, Mxolisi Brendon; Johnson, Oluwagbenga T.; Babalola, Bukola Joseph

doi:10.1007/s00170-019-03698-y

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…On the other hand, in most of the studies and evaluations in the field of metallurgy, nonisothermal tempering procedure was simplified assuming a constant heating rates rather than a variable one which is actually experienced by the products in the real production cycle. For example studies like those of Chenge et al [7], Ding et al [8], Kekana et al [9], and Bakhsheshi-Rad et al [10] focusing on different metallurgical aspects like microstructure evolutions, phase transformations, carbides precipitation during tempering process and their subsequent effect on the mechanical properties of the product, used constant heating rates in their investigations. The problem is more acute in the case of large size products (that encompass high temperature gradient from one end to another) at high temperatures due to operational difficulties and high costs of experimentation.…”

Section: Introductionmentioning

confidence: 99%

Optimization of furnace residence time and loading pattern during heat treatment of large size forgings

Arkhazloo

Bazdidi–Tehrani

Morin³

et al. 2021

Int J Adv Manuf Technol

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A combination of unsteady 3D CFD simulations and experimental temperature measurements was employed to determine the effect of loading patterns on the temperature distribution within steel forgings inside a gas-fired heat treatment furnace. This was aimed to obtain a more homogenous temperature distribution. Besides, a hybrid methodology using 3D numerical simulations and a high-resolution dilatometer allowed improving residence time of forgings inside the heat treatment furnace. The influence of the loading patterns and skids on temperature distribution and residence time of forgings was examined using thermal analysis four different loading patterns.Comprehensive unsteady thermal analysis of the products heating allowed quantifying the impact of skids usage and their dimensions on the extent of the uniformity of temperature distribution.The results were interpreted in terms of the inter-relationship between the skids usage, their geometry, absorbed radiation and convective heat fluxes. The analysis showed that temperature non-uniformities of up to 331 K could be produced for non-optimum loading patterns. Using the developed CFD approach it was possible to reduce the temperature non-uniformity of different sizes of blocks up to 32% via changing the loading pattern inside the furnace. Further, the slab's residence time was improved by almost 15.5% when employing the proposed hybrid approach. This approach could directly be applied to the optimization of different heat treatment cycles of forged blocks in different grades of steels.

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Section: Introductionmentioning

confidence: 99%

Optimization of furnace residence time and loading pattern during heat treatment of large size forgings

Arkhazloo

Bazdidi–Tehrani

Morin³

et al. 2021

Int J Adv Manuf Technol

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“…This was done using a load of 0.98 N on a polished surface, at a dwell time of 15 second and the average of seven indentations were taken. The hardness results (HV) were used to estimate the tensile strength and yield strength of the consolidated samples [31] [32]. The minimum and maximum percentage error of the predicted value and measured yield strength is within 0.2 and 13.8 MPa.…”

Section: Starting Samplesmentioning

confidence: 99%

The Influence of Dispersion Time On The Mechanical Properties of Spark Plasma Sintered Carbon Nanotubes Reinforced Nickel-Aluminium Matrix Composites

Ayodele

Awotunde

Babalola

et al. 2021

Preprint

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Nickel (Ni) and aluminium (Al) powders were milled with carbon nanotubes (CNT) by employing the high-speed ball milling approach, and the consolidation was achieved by spark plasma sintering technology (SPS). The microstructural evolution of the milled samples and consolidated samples were examined, and the mechanical properties were investigated. The outcome indicated the agglomeration of CNT within the NiAl matrix, and the CNT dispersions improved with the milling duration. The structural integrity of the CNT was evaluated using the Raman analysis which depicted that the ID/IG ratio decreased from 0.986 to 0.867 as the high-speed ball milling was longer, which also depicts more damage to the CNT. The microhardness of the consolidated composite was enhanced from 287.7 HV-320.4 HV due to better dispersion of CNT within the matrix metal. Furthermore, the predicted tensile strength and yield strength of the composite improved from 4011.9 MPa-4428.8 MPa, and from 5747.9 MPa-6389.3 MPa.

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“…Mechanical properties can be improved by applying appropriate heat treatment, Hot Isostatic Pressing (HIP), or plastic deformation processing [23,24]. Researchers [25,26] evaluated the effects of heat treatments on sintered nickel-based alloys. They concluded that the microhardness increased after aging for 2 h and decreased after a prolonged aging time at a higher temperature.…”

Section: Introductionmentioning

confidence: 99%

High Cycle Fatigue Behaviour of 316L Stainless Steel Produced via Selective Laser Melting Method and Post Processed by Hot Rotary Swaging

et al. 2023

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This paper deals with a study of additively manufactured (by the Selective Laser Melting, SLM, method) and conventionally produced AISI 316L stainless steel and their comparison. With the intention to enhance the performance of the workpieces, each material was post-processed via hot rotary swaging under a temperature of 900 °C. The samples of each particular material were analysed regarding porosity, microhardness, high cycle fatigue, and microstructure. The obtained data has shown a significant reduction in the residual porosity and the microhardness increase to 310 HV in the sample after the hot rotary swaging. Based on the acquired data, the sample produced via SLM and post-processed by hot rotary swaging featured higher fatigue resistance compared to conventionally produced samples where the stress was set to 540 MPa. The structure of the printed samples changed from the characteristic melting pools to a structure with a lower average grain size accompanied by a decrease of a high fraction of high-angle grain boundaries and higher geometrically necessary dislocation density. Specifically, the grain size decreased from the average diameters of more than 20 µm to 3.9 µm and 4.1 µm for the SLM and conventionally prepared samples, respectively. In addition, the presented research has brought in the material constants of the Hensel-Spittel formula adapted to predict the hot flow stress evolution of the studied steel with respect to its 3D printed state.

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Densification behaviour and the effect of heat treatment on microstructure, and mechanical properties of sintered nickel-based alloys

Cited by 7 publications

References 18 publications

Optimization of furnace residence time and loading pattern during heat treatment of large size forgings

Optimization of furnace residence time and loading pattern during heat treatment of large size forgings

The Influence of Dispersion Time On The Mechanical Properties of Spark Plasma Sintered Carbon Nanotubes Reinforced Nickel-Aluminium Matrix Composites

High Cycle Fatigue Behaviour of 316L Stainless Steel Produced via Selective Laser Melting Method and Post Processed by Hot Rotary Swaging

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