Solution Treatment Study of Inconel 718 Produced by SLM Additive Technique in View of the Oxidation Resistance

2018 ◽  
Vol 20 (11) ◽  
pp. 1800351 ◽  
Author(s):  
Michele Calandri ◽  
Diego Manfredi ◽  
Flaviana Calignano ◽  
Elisa Paola Ambrosio ◽  
Sara Biamino ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Inconel 718 ◽  
Solution Treatment ◽  
Additive Technique

scholarly journals Optimization of the Post-Process Heat Treatment of Inconel 718 Superalloy Fabricated by Laser Powder Bed Fusion Process

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 144
Author(s):  
Eslam M. Fayed ◽  
Mohammad Saadati ◽  
Davood Shahriari ◽  
Vladimir Brailovski ◽  
Mohammad Jahazi ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Mechanical Performance ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Homogenization Treatment ◽  
Powder Bed ◽  
Post Process ◽  
High Fraction

In the present study, multi-objective optimization is employed to develop the optimum heat treatments that can achieve both high-mechanical performance and non-distinctive crystallographic texture of 3D printed Inconel 718 (IN718) fabricated by laser powder bed fusion (LPBF). Heat treatments including homogenization at different soaking times (2, 2.5, 3, 3.5 and 4 h) at 1080 °C, followed by a 1 h solution treatment at 980 °C and the standard aging have been employed. 2.5 h is found to be the homogenization treatment threshold after which there is a depletion of hardening precipitate constituents (Nb and Ti) from the γ-matrix. However, a significant number of columnar grains with a high fraction (37.8%) of low-angle grain boundaries (LAGBs) have still been retained after the 2.5 h homogenization treatment. After a 4 h homogenization treatment, a fully recrystallized IN718 with a high fraction of annealing twins (87.1%) is obtained. 2.5 and 4 h homogenization treatments result in tensile properties exceeding those of the wrought IN718 at both RT and 650 °C. However, considering the texture requirements, it is found that the 4 h homogenization treatment offers the optimum treatment, which can be used to produce IN718 components offering a balanced combination of high mechanical properties and adequate microstructural isotropy.

Influence of Nitrogen on Oxidation Resistance of Automotive Steel Grades

2020 ◽  
Vol 835 ◽  
pp. 83-92
Author(s):  
Saeed Ghali ◽  
Mamdouh Eissa ◽  
Hoda El-Faramawy ◽  
Azza Ahmed ◽  
Fathy Baiomy ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Stainless Steels ◽  
Oxidation Process ◽  
Diffusion Mechanism ◽  
Solution Treatment ◽  
Mass Gain ◽  
Optical Microscope ◽  
Partial Replacement ◽  
Steel Grades ◽  
Automotive Steel

With the objective of partial and total replacement of nickel by nitrogen in austenitic exhausted valve steel X45CrNiW18-9, a program of work with series of experimental heats was designed. Experimental heats were carried out in 10 Kg. induction furnace under nitrogen pressure. The chemical composition of produced stainless steels was determined. The produced automotive steel grades were forged. The nitrogen contents were determined. The produced forged stainless steels were subjected to solution treatment at 1050 °C for 1 hour, followed by water cooling. Isothermal oxidation test is used to detect the behavior of new grades at different temperatures in air for solution treated stainless steels. The mass gain was measured for samples exposed to air at temperatures (500 °C, 600 °C, 700 °C, 800°C) for different time intervals, up to 1000 hrs. The oxide layer thickness for two selected steels was investigated by using optical microscope. XRD was used to detect types of oxides which are formed during oxidation process at 800 °C for 1000 hrs for represented investigated exhausted valve steels. Scanning Electron Microscope was used to make scan steels surface, after heating at 500 °C and 800 °C for l000hr. The mechanism of the oxidation of developed steels was investigated. It was found controlled by diffusion mechanism and the kinetic of oxidation process is parabolic. Oxidation rate of the investigated stainless steels for times, up to 8 h and between 200 andl000 h, at all investigated temperatures (500 °C - 800 °C), is parabolic and the oxidation is diffusion controlled. While in the time region 10 to 200 h, it obeys combined mechanisms. Partial replacement of nickel, by nitrogen, improves the oxidation resistance in air at temperature range 500°C - 800°C.

Fabrication of highly compact Inconel 718 alloy by spark plasma sintering and solution treatment followed by aging

Vacuum ◽  
2019 ◽  
Vol 163 ◽  
pp. 194-203 ◽  
Author(s):  
Shuaijiang Yan ◽  
Qingxiang Wang ◽  
Xing Chen ◽  
Chengsong Zhang ◽  
Guodong Cui
Keyword(s):  
Spark Plasma Sintering ◽  
Inconel 718 ◽  
Solution Treatment ◽  
Inconel 718 Alloy ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Effects of the γ″-Ni3Nb Phase on Mechanical Properties of Inconel 718 Superalloys with Different Heat Treatments

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 151
Author(s):  
Li-Shi-Bao Ling ◽  
Zheng Yin ◽  
Zhi Hu ◽  
Jin-Hui Liang ◽  
Zhi-Yong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Inconel 718 ◽  
Hot Isostatic Pressing ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Strengthening Mechanism ◽  
Morphological Observation ◽  
Isostatic Pressing ◽  
Direct Aging

The effects of the γ″-Ni3Nb phase on the mechanical properties of Inconel 718 superalloys, with standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging, were characterized by morphological observation, X-ray diffraction, and tensile experiments. The results of the morphological observation revealed that many fine γ″ precipitates of ~26.49 ± 1.82 nm in mean size were formed in all samples. However, the relatively coarser γ″ precipitates formed in the grain boundaries were only observed in the sample treated with hot isostatic pressing + direct aging. The yield strengths of the hot isostatic pressing + direct aging sample at room temperature and at 650 °C both exhibited the maximum values about 993 ± 5.7 and 811 ± 12.6 MPa, respectively. The γ″ precipitate was considered to be the dominant strengthening phase in the sample according to the lattice misfits (ε) of γ/γ″. The strengthening mechanism of the samples can be explained as the coherency strain strengthening of fine γ″ precipitates. Moreover, due to the coarser γ″ precipitates in the grain boundaries, dislocation-cut ordered particle strengthening also occurred in the sample after hot isostatic pressing + direct aging treatment.

Hardness and Microstructure Change During Annealing Process of a Modified Inconel-718

1985 ◽  
Vol 43 ◽  
pp. 340-341
Author(s):  
Chen-Ti Hu ◽  
Yau-Tsurng Syu
Keyword(s):  
Inconel 718 ◽  
Hot Forging ◽  
Solution Treatment ◽  
Melting Furnace ◽  
Annealing Process ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Rockwell Hardness ◽  
Inconel 718 Alloy ◽  
Complete Investigation

A modified Inconel 718 alloy with a higher content of Mo and lower was prepared from metals of electrolytic grade purity with a L-H IS 8/III vacuum induction melting furnace. The results of chemical analysis were shown in Table 1. After about 80 pet reduction in thickness with hot forging, material was then subjected to 1200°C solution treatment for one hour, air cool and 720°C ageing treatment for 16 hour, air cool. An uniformly dispersed γ’ and γ” precipitates was obtained.Material was plastically deformed to 70 pet reduction in thickness by cold rolling treatment. Then all specimens were divided into four groups and annealed in salt baths with temperatures of 750°C, 850°C, 920°C and 1060°C, respectively. 850°C was chosen to conduct a complete investigation of interior microstructures of different time periods: (1) 2 sec (2) 5 sec (3) 10 sec (4) 30 sec (5) 1 min (6) 5 min (7) 10 min (8) 20 min (9) 35 min (10) 1 hr (11) 2hr. Hardness of all thermomechanically treated specimens were examined with a Rockwell Hardness machine, using RC and RB scales.

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