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Heat treatment for metal additive manufacturing Vrije Universiteit Brussel

Majid Laleh, Esmaeil Sadeghi, Reynier I. Revilla, Qi Chao, Nima Haghdadi, Anthony Hughes, Wei Xu, Iris De Graeve, Ma Qian, Ian Gibson, et al.
Metal additive manufacturing (AM) refers to any process of making 3D metal parts layer-upon layer via the interaction between a heating source and feeding material from a digital design model. The rapid heating and cooling attributes inherent to such an AM process result in het erogeneous microstructures and the accumulation of internal stresses. Post-processing heat treatment is often needed to modify the microstructure and/or alleviate ...

Impact of surface oxides on steel on hydrogen absorption and desorption Vrije Universiteit Brussel

Tim Rubben
The problem of hydrogen assisted cracking (HAC) of steel has been known for over 140 years. However, it is still not solved nor fully understood. The presence of
atomic hydrogen in a metal can cause important ductility loss, known as “hydrogen embrittlement (HE)”, and can be introduced during the production and processing
of steel or during its use, referred to as internal hydrogen embrittlement (IHE) and hydrogen environment ...

Revealing the stress corrosion cracking initiation mechanism of alloy 718 prepared by laser powder bed fusion assessed by microcapillary method Vrije Universiteit Brussel

Arshad Yazdanpanah, Mattia Franceschi, Reynier I. Revilla, Saeed Khademzadeh, Iris De Graeve, Manuele Dabala
Stress corrosion cracking (SCC) behaviour of L-PBF processed alloy 718 in chloride-containing solution was revealed, utilizing the microcapillary method under constant tensile loading. Results were compared with conventionally produced counterparts. Passive layer resistance was compared quantitatively by implementing electrochemical polarization experiments, in as-received and under tensile loading states. Superior corrosion and SCC resistance ...

New insights into the mechanism of localised corrosion induced by TiN-containing inclusions in high strength low alloy steel Vrije Universiteit Brussel

Chao Liu, Reynier I. Revilla, Xuan Li, Shufeng Yang, Dawei Zhang, Herman Terryn, Xiaogang Li

This work investigated the chemical and electrochemical mechanisms of localised corrosion triggered by CaS·xMgO·yAl2O3·TiN complex inclusions in high strength low alloy steel (HSLAS) under a simulated marine environment. Special focus was given to the role of the TiN portion of the inclusion on the initiation and growth of the corrosion pits. The thermodynamic process of pitting initiation was investigated by Gibbs free energy, Pourbaix ...

Effect of Thermal Treatment on Corrosion Behavior of AISI 316L Stainless Steel Manufactured by Laser Powder Bed Fusion Vrije Universiteit Brussel

Francesco Andreatta, Alex Lanzutti, Reynier I. Revilla, Emanuele Vaglio, Giovanni Totis, Marco Sortino, Iris De Graeve, Lorenzo Fedrizzi
The effect of post-processing heat treatment on the corrosion behavior of AISI 316L stainless steel manufactured by laser powder bed fusion (L-PBF) is investigated in this work. Produced stainless steel was heat treated in a broad temperature range (from 200 °C to 1100 °C) in order to evaluate the electrochemical behavior and morphology of corrosion. The electrochemical behavior was investigated by potentiodynamic and galvanostatic polarization ...

Growth kinetics and passive behavior of the native oxide film on additively manufactured AlSi10Mg versus the conventional cast alloy Vrije Universiteit Brussel

Reynier I. Revilla, Herman Terryn, Iris De Graeve
This work studies the passive behavior and growth kinetics of the native oxide on additively manufactured AlSi10Mg and compares it with that of the conventional cast alloy, which presents a markedly different microstructure. With the use of a scanning Kelvin probe force microscopy (SKPFM)-based methodology, the growth kinetics of native oxide films on these alloys was examined. The microstructure of these materials had a great impact on the ...

Trend Removal in Measurements of Best Linear Time-Varying Approximations – with Application to Operando Electrochemical Impedance Spectroscopy Vrije Universiteit Brussel

Noel Hallemans, Rik Pintelon, Xinhua Zhu, Thomas Marcel Collet, Meisam Dabiri Havigh, Benny Wouters, Reynier I. Revilla, Raf Claessens, Kristof Ramharter, Annick Hubin, et al.
Equilibria evolving over time, also called trends, are often present in ongoing measurements of real-life systems. These trends are considered as disturbances when computing the Best Linear Time-varying Approximation (BLTVA) of the system. Current techniques for dealing with trends in BLTVA measurements consist of modelling the trend with a finite number of basis functions. However, in measurements with dominant trends, the trend cannot always ...

The Hot-Stamping Effect on the Corrosion Properties of the 22MnB5 Steel Coated with Hot-Dip Aluminum-Silicon Assessed by a Salt Spray Test and Raman Spectroscopy Vrije Universiteit Brussel

Camila Pucci Couto, Kitty Baert, Isolda Costa, Zehbour Panossian, Iris De Graeve, Herman Terryn, Jesualdo Luiz Rossi, Reynier I. Revilla

The effect of hot stamping on the corrosion properties of boron-manganese 22MnB5 steel coated with hot-dip aluminum-silicon was evaluated under severe conditions by a continuous salt spray test (SST). The corrosion mechanism changed from localized to generalized, as cathodic precipitates were not present after hot stamping. Intrinsic defects in press-hardened steel samples were the reason for severe damage in both metallic coating and steel ...

Influence of austenitisation temperatures during hot stamping on the local electrochemical behaviour of 22MnB5 steel coated with hot-dip Al-Si Vrije Universiteit Brussel

Camila Pucci Couto, Reynier I. Revilla, Rodolfo Politano, Isolda Costa, Zehbour Panossian, Iris De Graeve, Jesualdo Luiz Rossi, Herman Terryn

Scanning Kelvin probe force microscopy was used to evaluate the effect of austenitisation temperatures during hot stamping on the local electrochemical behaviour of 22MnB5 steel coated with hot-dip Al-Si. A variation in the austenitisation temperature around 50 °C substantially altered the coating morphology as well as the local electrochemical behaviour of the system (coating/steel). Both coating layer and steel substrate became nobler as ...

Depth profiling approach to evaluate the influence of hot stamping on the local electrochemical behaviour and galvanic series of hot-dip Al-Si coating on 22MnB5 steel Vrije Universiteit Brussel

Camila Pucci Couto, Francesco Andreatta, Isolda Costa, Zehbour Panossian, Iris De Graeve, Herman Terryn, Jesualdo Luiz Rossi, Reynier I. Revilla

The influence of hot-stamping process on the corrosion properties of Al-Si coating on 22MnB5 steel was locally evaluated using a depth profiling approach combining GDOES and electrochemical micro cell. The results highlight the complexity of the system and the high dependence of the local galvanic series on the hot-stamping process. Due to iron diffusion from the steel substrate into the coating, the Al-rich layers presented active behaviour, ...