Metallurgical and Materials Transactions 

About: Metallurgical and Materials Transactions is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Microstructure & Chemistry. It has an ISSN identifier of 1073-5623. Over the lifetime, 558 publications have been published receiving 603 citations. The journal is also known as: Metallurgical and Materials Transactions B - Process Metallurgy and Materials Processing Science.

On the Influence of Alloy Composition on the Additive Manufacturability of Ni-Based Superalloys

Abstract: Abstract The susceptibility of nickel-based superalloys to processing-induced crack formation during laser powder-bed additive manufacturing is studied. Twelve different alloys—some of existing (heritage) type but also other newly-designed ones—are considered. A strong inter-dependence of alloy composition and processability is demonstrated. Stereological procedures are developed to enable the two dominant defect types found—solidification cracks and solid-state ductility dip cracks—to be distinguished and quantified. Differential scanning calorimetry, creep stress relaxation tests at 1000 °C and measurements of tensile ductility at 800 °C are used to interpret the effects of alloy composition. A model for solid-state cracking is proposed, based on an incapacity to relax the thermal stress arising from constrained differential thermal contraction; its development is supported by experimental measurements using a constrained bar cooling test. A modified solidification cracking criterion is proposed based upon solidification range but including also a contribution from the stress relaxation effect. This work provides fundamental insights into the role of composition on the additive manufacturability of these materials.

Simulation of eutectic solidification structures of binary alloys: a multiparticle diffusion limited aggregation model

Abstract: The (isothermal) eutectic solidification structures of binary alloys have been simulated using a two-dimensional monte carlo model. The model takes into account simultaneous diffusion of all liquid atoms, incorporates the energy contributions of like and unlike nearest and next-nearest neighbor bonds in the solid on solidification, and allows surface rearrangement at the solid-liquid interface. It has been demonstrated that results obtained from this model exhibit phenomena observed during eutectic solidification in practice, for example, the passage of the growth rate through a maximum upon decreasing temperature. Particular attention has been devoted to the effect of growth parameters, such as the next nearest neighbor interaction in the solid and the surface relaxtion length, on the morphology of the growing solid phase.

Novel Surface Topography and Microhardness Characterization of Laser Clad Layer on TC4 Titanium Alloy Using Laser-Induced Breakdown Spectroscopy and Machine Learning

Abstract: Abstract This study was performed to characterize surface topography and microhardness of 40 wt pct NiCrBSiC-60 wt pct WC hard coating on TC4 titanium after coaxial laser cladding via Laser Induced Breakdown Spectroscopy (LIBS) and machine learning. The high content of the hard WC particles is accomplished to enhance the abrasion wear resistance of such alloy. Various powder feeding rates were carried out during laser cladding process. The energy-dispersive X-ray analysis assured that W content in the metal matrix notably increased from 26.19 to 53.49 pct while the Ti content decreased from about 15.16 to 0.46 pct for the clad layer processed at 20 and 60 g min −1 , respectively. The LIBS measurements successfully estimated such elements’ concentration as well as the clad layers' topography indicating that the effect of material matrix is a crucial challenge. Therefore, canonical correlation analysis and Belsley collinearity diagnostics were established to identify the essential emission lines from the whole spectra. Then, an optimized adaptive boosted random forest classifier was developed for microhardness investigation, with accuracy, sensitivity, and F1 score values of 0.9667. The results, confirmed by the metallurgical study, clarified that most of the titanium and tungsten emission lines have a significant impact on the surface topography as well as the microhardness values. The misclassification was attributed to the matrix effect such that the samples processed at 40 and 60 g min −1 were comparable in microstructure and chemical characterization unlike the one processed at 20 g min −1 . Vickers microhardness of the metal matrix coating increased with the increase in the powder feeding rate, which is assured by the quantitative classification model. Graphical Abstract