1,720,995 research outputs found
Solute Effects on Growth Restriction in Dilute Ferrous Alloys
Full text linkThe effect of dilute solute additions on growth restriction in binary ferrous alloys has been assessed by means of the heuristic growth restriction parameter (β) modelling framework (Fan et al. in Acta Mater. 152, 248–257, 2018). The CALPHAD (CALculation of PHAse Diagrams) methodology (Kaufman and Bernstein in Computer Calculation of Phase Diagrams, 1970) has been used to calculate β values from the liquidus slope m and the equilibrium distribution coefficient k values, at first approximation, in conjunction with the liquid-to-solid fraction to obtain true β values. Critical solute concentrations, below which solidification becomes partitionless, have also been calculated. Among 23 dilute binary ferrous alloy systems investigated, the five most efficient solutes on grain refinement are B, Y, O, S and C. A negative correlation, or inverse relationship, was observed between the true β values and the grain size values obtained from a study on experimental multicomponent dilute ferrous alloy systems (Li et al. in Metall. Mater. Trans. A 49 A, 2235–2247, 2018)
Effects of Superheat and Solute Additions on the Grain Size in Binary Copper Alloys
Full text link© The Author(s) 2019. By utilizing data from the literature, we examine the effects of superheat and solute additions on the grain size (as measured by columnar grain length) in binary copper alloys. Our investigation provides support for an Arrhenius-like behavior of the superheat on the grain size. We also find a correlation between the columnar grain length at a constant degree of superheat and the variation of the reciprocal of the true growth restriction factor (1/Q) with P, Mg, Mn, Pb, and Sn solute additions to be a power of law of 1/3, which gave a better fit than a linear one.EPSRC (UK
The Impact of Fused Filament Fabrication (FFF) Printing Profiles on 17-4 PH Green and Sintered Parts
No full textThe aim of this research is to characterize parts from innovative hybrid printing method for obtaining dense metal components using affordable fused filament fabrication (FFF). The introduction of Desktop Metal technology in 2015 really attracts an increase in industrial interest in the FFF printing of highly metal-filled filament. Even though FFF is a well-known process, there are not many studies on how to optimize the printing parameters for these feedstocks. The effects of the printing setting on producing high-quality green parts and enhancing the mechanical properties of the finished 17-4 PH metallic parts are investigated in this work. The influence of four printing profiles provided by a BASF plugin for Ultimaker Cura slicing software, obtained by combining different printing parameters is investigated. The ASTM E8 tensile test is used to determine the mechanical characteristics of the finished metal components. To identify differences in morphology, optical and scanning electron microscopy (SEM) observations are made on both sections of green and sintered samples. The effect of printing parameters on shrinkage and density are also taken into consideration. The findings demonstrate the importance of optimizing the printing of the green parts in order to produce full metal components that are both strong and dense
Study of the Dynamic Response of a Sinterized Material to a Seismic Excitation for Knowledge Enhancement in an Expert System for Rapid Prototyping
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Roughness investigation of steel 316L parts fabricated by Metal Fused Filament Fabrication
No full textMetal Fused Filament Fabrication attracted significant interest in both academia and industry to fabricate net-shape engineering components via low-cost 3D printing technology. However, many fields such as the roughness control and prediction are still unexplored. These aspects are very important to consider especially when the process is used for the fabrication of functional parts: the roughness, in fact, deeply influences the functionality of a component in terms of friction, contact deformation, heat, electric current conduction, etc. Aim of this work is to fulfill the lack of knowledge about the prediction of the obtainable roughness in this process. For the purpose an in-depth analysis of the effect of the processing parameters on surface roughness profiles obtained at green and sintered stages is reported. The experiment is planned using the Design of Experiments technique and the data are collected followed a rigid procedure developed for the scope. The results show that the profiles are markedly affected by the process parameters and depend upon the deposition angles. Green and sintered parts show different behaviors caused by different underling mechanisms. The complexity of the process is highlighted and described by regression models for different deposition angles. The models set allows for a multiple optimization in order to achieve processing parameters combinations able to satisfy desired requirements
On the Role of Dilute Solute Additions on Growth Restriction in Binary Copper Alloys
Full text linkThe effect of dilute solute additions on growth restriction in binary Cu alloys has been assessed at different degrees of superheat. Columnar grain length values from Northcott’s work (Northcott in J Inst Metals 62:101-136, 1938) for binary Cu alloys were plotted against the corresponding undercooling parameter (P), the reciprocal of the conventional (Qconv.) and true (Qtrue) growth restriction factor (Schmid-Fetzer and Kozlov in Acta Mater 59(15):6133-6144, 2011) values. It was found that there was no correlation between the columnar grain length values and P, 1/Qconv. and 1/Qtrue values for different solutes and cast at the same degree of superheat. Unlike P, Qconv., and Qtrue values, the heuristic growth restriction parameter (β) (Fan et al. in Acta Mater 152, 248-257, 2018) modeling framework in conjunction with the critical solute content (C*) for growth restriction fitted well to binary Cu alloys
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