Equilibrium Solidification Research Articles

Calculation and Experimental Verification of Zn–Al–Mg Phase Diagram

The liquid phase projection diagram, three-dimensional phase diagram, and vertical section diagram of the Zn–x%Al–x%Mg alloy system was calculated using the phase diagram calculation software Pandat. Simultaneously making full use of the self-developed hot-dip galvanizing process simulation machine by China Steel Research produced a 75%Zn–19%Al–6%Mg coating. A method combining phase diagram calculations and experimental verification was used to investigate the equilibrium phases and solidification process of the alloy. The microstructure of the 75%Zn–19%Al–6%Mg coating was studied using scanning electron microscopy and energy dispersive spectrometry. The results indicate that the coating structure consists of primary Al dendrite phase, MgZn2 inter-metallic compound and Zn-rich phase. There is no ternary eutectic structure in the coating structure. Al dendrites grow on the surface of the coating, while there are no Al dendrites on the cross-section. The experimental results strongly concur with the calculated results from the Pandat phase diagram. The solidification sequence of the 75%Zn–19%Al–6%Mg coating is L→L + Al→L + Al + MgZn2→Al + MgZn2 + Zn. The phase diagram guides industrial production significantly, avoiding the waste of transitional materials and zinc caused by small scale trial and error experiments, thus reducing unnecessary production costs. The factory can select a reasonable coating composition designing scheme in the phase diagram, based on the performance requirements of customers for the coating.

Transitioning solidification mode via electroplated Ni coatings in martensitic stainless steel resistance spot welds: new insights into fabricating tough microstructure

The present study addresses the enhancement of fracture toughness of martensitic stainless steel (MSS) spot welds by utilizing through electroplating of Ni on MSS sheets. The equilibrium and non-equilibrium solidification modelling showed that by Ni coating with 50 μm thick on 1.5 mm thick MSSs, the solidification mode changes from δ-ferrite to γ-austenite, leading to a weld nugget (WN) dominated by austenite grains. Moreover, electron backscatter diffraction (EBSD) and electron probe microanalysis (EPMA) showed that the other phases (martensite, δ-ferrite) appeared in band areas of WN owing to incomplete mixing of MSS and the Ni-coating. The tough microstructure in the Ni-coated MSS spot welds provided superior mechanical properties compared to non-coated welds, both in cross-tension (CT) and tensile-shear (TS) tests. Notably, the TS and CT strengths of the Ni-coated MSS spot welds showed a remarkable increase of 57% and 127%, respectively, in comparison to the conventional bare MSS spot welds. Furthermore, in terms of failure energy, the Ni-coated MSS spot welds demonstrated a substantial enhancement of 296% in TS and 520% in CT, when compared to their non-coated counterparts. This research study showcased the effectiveness of Ni electroplating as an industrial method for improving the spot weldability of MSSs.

Influence of Si contents on the microstructure and corrosion resistance of the Zn−Al−Mg−Si alloys

Hot dip galvanized products are widely used in various aspects of production and life due to their excellent corrosion resistance. Some studies have added a fourth trace alloying element to the zinc aluminum magnesium coating to form a quaternary alloy for better performance. This article prepared two different types of Zn−Al−Mg alloy ingots with trace amounts of Si added by induction melting, consisting of Zn1Al1Mg0.01Si and Zn1Al1Mg0.05Si, and solidified them in a heating furnace with argon gas protection atmosphere. The precipitation process of Zn1Al1Mg(0.01,0.05)Si alloy components under non equilibrium and equilibrium solidification conditions was calculated. The initial crystalline phase of the alloy and the initial solidification temperature were predicted through phase diagram calculations. The microstructure and phase types of the alloy were analyzed using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FE-SEM). The electrochemical Tafel curves of Zn1Al1Mg(0.01,0.05)Si with different Si contents showed that the Zn1Al1Mg0.05Si has the highest corrosion potential and Zn1Al1Mg0.01Si has the lowest corrosion current which means the 1Al1Mg0.01Si alloy possesses the highest corrosion resistance. The Nyqust curves and bode curves also showed that the practical impedance of 1Al1Mg0.01Si alloy is higher than that of 1Al1Mg0.05Si. Moreover, electron probe X-ray micro-analyzer(EPMA) reveals the distribution of Si elements in the Zn1Al1Mg(0.01,0.05)Si. At present, there is little research on the microstructure and properties of quaternary alloys containing silicon. Therefore, studying the influence of silicon content on the microstructure and properties of alloys is of great significance.

Thermodynamic databases of Ti-Al-Fe-V quaternary alloy systems and its application

Pandat software based on Calculations of phase diagram (CALPHAD) was used in this study. Six binary systems and four ternary systems in the Ti-Al-Fe-V system were evaluated, compared, and optimized. A thermodynamic database of Ti-Al-Fe-V titanium alloys was established by selecting the most recent, accurate, and self-consistent thermodynamic parameters. The database was used to simulate the organization of equilibrium solidification and non-equilibrium solidification alloys of Ti-10V-2Fe-3Al, Ti-10V-3Al-1Fe and Ti-10V-3Al. The precipitated phase fractions of Ti-10V-2Fe-3Al at different temperatures were calculated using the database. The effect of different Fe contents and aging temperatures on the phase composition of the Ti-10V-2Fe-3Al alloy is given in conjunction with the calculated results. There is good agreement with the experimental results for the heat treatment regimens given by the calculations. The above results show that thermodynamic calculations based on phase diagrams can guide the formulation of process parameters for alloy casting and heat treatment. The established thermodynamic database for Ti-Al-Fe-V titanium alloys is accurate and reliable.

Experimental investigation and kinetic analysis of Al–Zn–Mg alloy coating

The hot-dip 55 wt%Al–Zn-1.6 wt%Si-(0–3)wt.%Mg alloy coatings were experimentally investigated, and the solidification behaviors and hot cracking susceptibility were simulated by means of CALPHAD (CALculation of PHAse Diagrams) method. The scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA) and glow discharge spectrometer method (GDS) were utilized to determine the microstructures and the distribution of elements of the Al–Zn–Mg alloy coatings with different Mg contents. It is discovered that with the increase of Mg content, the percentage of the eutectic microstructure scales up, and the surface quality of the alloy coating is improved. Meanwhile, the bending properties of Al–Zn–Mg coatings with different Mg contents still requires further improvement according to the present bending test. Subsequently, the equilibrium solidification processes of the coatings were calculated using thermodynamic approach. In general, the calculated results reflect the solidified phases and the precipitated temperatures according to theory of equilibrium solidification. However, there still exist discrepancies between the thermodynamic calculation results and the observed experimental results during the practical galvanizing process, because the cooling rates were not taken fully into consideration. Consequently, the kinetic analysis was carried out to obtain the secondary dendrite arm spacing under different cooling rates. The cracking susceptibility index (CSI) was also calculated to predict the hot workability of the Al–Zn–Mg alloy coating. In summary, the appropriate increase of the cooling rate turns out be the effective approach to benefit the microstructure and the corrosion resistance of the Al–Zn–Mg coatings in the practical galvanizing process, and the coating is not suitable for the hot stamping process.

Hot cracks in camshaft casting: initiation and propagation

ABSTRACT In this paper, a numerical simulation method based on the camshaft casting process and crack expansion was proposed to study the propagation characteristics of casting hot cracks. The dynamic visualisation process of hot crack growth indicates that the formation of hot tear is dominated by opening mode cracks. And during the propagation process, the equivalent stress intensity factor at the crack front first decreases and then increases. Furthermore, the propagation characteristics of the crack under different hot tear initiation conditions were studied by this method. The results reveal that the expansion ability of a hot crack is affected by the equilibrium solidification scale, solidification sequence, and solidification path of the casting. Finally, using the microscopic morphology of the cracks, the semi-quantitative analysis of the elements illustrates that the carbon content decreases sharply at the crack formation site, while manganese and sulphur are relatively rich.

Phase change and combustion of iron particles in premixed CH[formula omitted]/O[formula omitted]/N[formula omitted] flames

Metal powder is a promising carbon-free and recyclable energy carrier. Direct combustion of the micron-sized iron particles involves complex physical and chemical processes, such as heat transfer, surface reaction, and phase change. In this work, computational modelling of these processes is investigated and validated against experiments. A single iron particle combustion and phase change model is proposed in an Eulerian–Lagrangian framework. The new phenomenological model considers five stages, i.e., solid phase oxidation, melting of iron oxides and raw iron, liquid phase oxidation, cooling of liquid iron oxides, and solidification of super-cooled liquid iron oxides. The proposed model is first validated and then adopted in simulations of micron-sized iron particle combustion in premixed CH4/O2/N2 flames to study the effects of ambient temperature and oxygen concentration on single iron combustion. Results show that the new model is capable of replicating the melting, heterogeneous surface reaction, cooling, and solidification processes. Two-stage solidification is observed in experiments and modelled in simulations. This two-stage solidification includes a fast solidification with a significant temperature rise (∼150–200 K) and a thermal equilibrium solidification featuring a constant temperature and a slight particle radiant intensity decrease. In addition, a diffusion-controlled mechanism is identified during the melting process, in which the oxygen concentration dominates the melting time and the subsequent burning time. Furthermore, it is found that the reaction between iron and CH4/O2/N2 flame products, such as CO2 and H2O, plays a non-negligible role in the iron combustion process.

An analytical framework for predicting the total freezing delay time of water droplet impact on hydrophobic solid surfaces

An analytical framework is developed to investigate the impact and freezing delay of a water droplet on solid surfaces, particularly hydrophobic ones, at subfreezing temperatures. Submodules for droplet dynamics, supercooling, nucleation and recalescence, and equilibrium solidification are developed for different droplet impact and freezing stages. These submodules are then integrated to estimate the total freezing delay time per unit mass of the water droplet. It is found that the nucleation time depends on the impact height, surface temperature, droplet impact temperature, and the droplet-substrate contact angle, while the solidification time depends on the droplet size, the nucleation temperature, and the droplet final contact diameter, which is related to the initial droplet diameter, the Weber number, the Reynolds number, and contact angle. The analytical model is validated with results from droplet freezing experiments in a subfreezing environment. By simplifying the complex droplet dynamics, nucleation, and freezing processes, the new analytical framework provides a useful way to estimate the total freezing time of impacting water droplets on hydrophobic surfaces. Its accuracy needs to be improved for practical engineering applications.

Influence of Si and Mo on the Sigma-Phase Precipitation in S32750 Super Duplex Stainless Steel Slab

In this study, we investigated the effect of Si and Mo on the sigma-phase precipitation in S32750 super duplex stainless steel slab. The activity for Mo with increasing Si and Mo was calculated by the Wagner formula, and the equilibrium solidification phase diagrams of S32750 duplex stainless steels with different Si and Mo contents were calculated using the thermo-calc software. The sigma phase precipitated mainly at ferrite/austenite phase boundaries and grew up towards the interior of ferrite phase in S32750 SDSS slab. The area fraction and size of the sigma phases significantly increased with increasing Mo content and Si content. Also, the increment in Mo and Si content affected the Mo concentration in sigma phase. The sample（Mo:3.4%,Si：0.3%） had a lowest sigma-phase area fraction of 2.84% and had lowest Mo content in σ phase.The calculation results showed that the increase of Mo and Si content increased the initial precipitation temperature and maximum precipitation amount of σ phase in S32750 SDSS equilibrium phase diagram. The activity of Mo also increased with increasing Si content and Mo content. That is, Mo and Si elements promoted the precipitation of σ phase.

Toward sustainability for upcycling SoG-Si scrap by an immersion rotational segregation purification process

Recycling solar grade silicon (SoG-Si) scrap is critical for the sustainability of solar energy and fulfilling to close material loops in circular economics. A major challenge is to control trace impurities efficiently in short time for upgrading scrap to a level of SoG-Si. Here, a new immersion rotational separation purification (IRSP) process is developed to enhance trace impurities removal and the crystal growth from remelted metal by driving the rotating shear flow to improve the efficiency of solute and heat transfer. In a departure from conventional practice that forces extremely low solidification rate limited by the diffusion layer depth at approximately equilibrium solidification interface, here IRSP achieves the deep removal of impurities and the increase of solidification rate by the non-equilibrium rotating solidification interface. In the non-equilibrium solidification process caused by mold rotation, the rotating shear flow not only reduces the diffusion layer depth to improve impurity removal efficiency, but also increases the temperature gradient of the melt at the solidification front that is conducive to the increase of crystal growth rate. The new method is applicable to molten Si and the production of SoG-Si (99.9998%) has been demonstrated, which is able to improve the quality of recycled SoG-Si requiring a low energy input. It is expected that this process helps close high purity Si material loops, reduce resource consumption and the carbon footprint of the photovoltaic industry.

Effect of the Synthesis Route on the Microstructure of HfxTi(1−x)NbVZr Refractory High-Entropy Alloys

In the present work, the effects of (i) Ti replacement by Hf and (ii) the synthesis method on microstructure and crystal structure evolution in the high-entropy alloy HfxTi(1−x)NbVZr are reported. The results of scanning electron microscopy and X-ray diffraction analysis of alloys prepared by both arc-melting and induction-melting are compared with theoretical thermodynamic calculations using the CALPHAD approach. The non-equilibrium thermodynamic calculations agree well with the experimental observations for the arc-melted alloys: a mixture of body-centered cubic (BCC) and cubic C15 Laves phases occurs for low-Ti-concentration alloys and a single BCC phase is obtained for high-Ti alloys. The agreement is not as good when using the induction-melting method: equilibrium solidification calculations predict that the most stable state is a phase mixture of BCC, hexagonal close-packed, and a cubic C15 Laves phase, while experimentally only one BCC and one hexagonal C14 Laves phase were found. The estimation of the exact cooling rate and the lack of a thermodynamic database can explain the difference. In addition, for both methods, the thermodynamic calculation confirms that for a high Ti concentration, the BCC phase is stable, whereas phase separation is enhanced with a higher Hf concentration.

Variation of liquation cracking susceptibility for over–aged 247LC superalloy repair weld heat–affected zone

In this study, the liquation cracking temperature range (LCTR) of over-aged 247LC superalloy repair welds was quantitatively evaluated using spot-Varestraint testing, especially for application in the repair weld heat-affected zone (HAZ). The metallurgical mechanism of the evaluated liquation cracking susceptibility and variation of the LCTRs of the over-aged 247LC superalloys was clarified by analyzing the microstructural characteristics at the liquation cracking surface, and using thermodynamic calculations. From the spot-Varestraint tests of the over-aged materials, the LCTR was quantitatively evaluated to be 410 and 620 K for the 500 and 1000 h over-aged specimens, respectively. These results demonstrate that the over-aged 247LC superalloys face significant and serious liquation cracking susceptibility in repair weld HAZ. Based on local element distributions at the liquation cracking surface, analyzed by transmission electron microscopy and the Thermo-Calc calculations, the underlying metallurgical mechanism of high LCTRs of overaged materials could be attributed to the precipitation of fine MC and M6C carbides during the over-aging treatment. The carbides promote local liquation at the interface between the gamma phase at temperatures lower than the equilibrium solidus (1530 K) of the 247LC. The estimated liquation initiation temperatures at the MC/γ and γ/M6C interfaces were 1125 and 1420 K, respectively.

Discussion of the Segregation and Low Hardness of Large-Diameter M3 High-Speed Steel Produced by Spray Forming.

As an advanced near-net-shape processing method in which directly preformed, semi-finished products are created from liquid metals, spray forming has become popular in the development and application of new materials and is supporting industrialization. However, as investigated in this work, the problems of segregation and low hardness exist in the actual industrialization process, particularly for large-diameter M3 high-speed steel. It was here found that the annual ring segregation morphologies were mostly distributed from the edge to 1/2R, with a large number of stripes primarily enriched in C, Mo, and Cr elements, and the degree of segregation was mild. The ring segregation was located at the 1/2R position, where the main elemental enrichments were C, W, Mo, Cr, and V, and the segregation degree was severe. The formation of segregation during deposition is described based on an equilibrium solidification model. A slow cooling rate and heat dissipation from the surface to the inside were judged to be the main factors causing segregation and changes in the carbide morphology. In terms of hardness, with the increase in the quenching temperature to 1230 °C, the tempering hardness increased significantly. The analysis shows that a faster cooling rate in the atomization stage caused the solidified droplets to exhibit rapid solidification characteristics, and there was a higher proportion of MC carbide in the deposited billet. MC carbides cannot be fully dissolved using the conventional heat treatment process, which decreases the C, Cr, Mo, and V contents in the solution and, thus, reduces the secondary hardening capability. The findings show that, when the spray forming process is used to prepare large-diameter materials, it should not be considered a rapid solidification technology simply because of its atomization stage. Moreover, more attention should be paid to the influence of microstructure transformation during atomization and deposition.

Metastable phase separation and duplex metallic glass formation of liquid Zr<sub>35</sub>Al<sub>23</sub>Ni<sub>22</sub>Gd<sub>20</sub> alloy

Duplex metallic glass with two amorphous phases has been extensively investigated for desirable strength and plasticity. In this paper, the metastable phase separation and dual amorphous phase formation of liquid Zr<sub>35</sub>Al<sub>23</sub>Ni<sub>22</sub>Gd<sub>20</sub> alloy under substantial undercooling condition and rapid cooling condition are studied by drop tube technology. The equilibrium solidification structure consists of three crystalline phases, while the critical undercooling temperature of metastable phase separation is determined to be 516 K (0.37<i>T</i><sub>L</sub>). The separated Zr-rich liquid phase undergoes amorphous transition and becomes amorphous AM-Zr phase with the composition of Zr<sub>45</sub>Ni<sub>23</sub>Al<sub>23</sub>Gd<sub>9</sub> when alloy undercooling is increased to 624 K (0.45<i>T</i><sub>L</sub>). After that, the Gd-rich liquid phase forms amorphous AM-Gd phase with the composition of Gd<sub>39</sub>Al<sub>22</sub>Ni<sub>20</sub>Zr<sub>19</sub> at larger undercooling of 714 K (0.52<i>T</i><sub>L</sub>). With the increase of liquid undercooling and cooling rate, the kinetic mechanism of metastable phase separation changes from nucleation and growth type to spinodal decomposition type, and consequently the microstructure of dual amorphous phases transforms from a spherical morphology to a reticular structure. The average hardness and Young’s modulus, which are influenced by free volume, phase volume fraction and structure of dual amorphous phases, exhibit a complex variation of first increasing and then decreasing with the decrease of alloy droplet size. The formation of dual amorphous phases is in favor of the energy dissipation and the generation of multiple shear bands during mechanical compression, which improves the plasticity for this kind of amorphous alloy.

Investigation of dendrite growth, Nb segregation during laser IN718 deposition via volume of fluid-phase field modeling

In this work, a macro-micro VOF-PF (Volume of Fluid-Phase field) model is established to simulate the heat transfer, dendrite growth and Nb segregation during the laser IN718 deposition. According to calculated heat transfers, G increases, while Vp decreases, and the corresponding G×Vp decreases from top to bottom in the molten pool. The calculated the primary dendrite arm spacing (PDAS) using the PF model increases from top to bottom. Compared with other models, the calculated PDAS using the PF model considering the liquid-metal flow is closest to experiment measurements. During the dendrite growth, Nb is enriched in the interdendritic region, and finally is distributed in the droplet shape. The calculated actual solute distribution coefficient Cmin/Cmax decreases from 0.584 to 5.548 with the decrease of G×Vp, which follows the equilibrium solidification theory. According to dc/dy=G/ml, the liquidus slope ml is calculated as 0.05322wt.%/μm very close to the theoretical value 0.05394wt.%/μm. The simulated Nb concentrations in the matrix γ and Laves phases are 3.97wt.%, 13.3wt.% respectively, which are in good agreements with experimental 3.7wt.% and 13wt.%.

Relationship between Austenite‐Stabilizing Elements and Austenite Fraction in Near‐Rapidly Solidified Fe–Mn–Al–C Lightweight Steel

A peritectic reaction (liquid + δ‐ferrite → γ‐austenite) and eutectoid reaction (γ‐austenite → α‐ferrite + κ carbide) occur in the Fe–Mn–Al–C lightweight steel. Experimental results show that the main constituent phase of the near‐rapidly solidified Fe–Mn–Al–C lightweight steel is γ‐austenite and/or δ‐ferrite in this study, and the eutectoid reaction is restrained by the rapid cooling rate. With the increase of C content, the γ‐austenite fraction of near‐rapidly solidified medium‐Mn and high‐Mn Fe–Mn–Al–C lightweight steels increase significantly. However, in the early study, the increased Mn content had little effect on the γ‐austenite fraction of the near‐rapidly solidified Fe–(8/12/16)Mn–9Al–0.8C steel strips. This study attempts to reveal the reasons for the different effects of Mn and C on Fe–Mn–Al–C lightweight steel strip under near‐rapid solidification. It is found that the γ‐austenite fraction of the near‐rapidly solidified Fe–Mn–Al–C steel strip is closely related to the γ‐austenite fraction at the end of equilibrium solidification. This suggests that the main constituent phase of lightweight steel strip depends on its liquid–solid phase transformation under near‐rapid solidification and is seldom affected by solid phase transformation.

Potential Al-Fe Cast Alloys for Motor Applications in Electric Vehicles: An Overview

Iron is the main component of the earth's core, the most abundant element on the earth (about 35%), and it is relatively high in the sun and other stars. Also, it is a common and cheap metal in the manufacturing industry. Recently, with the rapid development of electric vehicles, more and more automotive companies are willing to develop new lightweight material for electric motors used in electrical vehicles. The iron–containing aluminum alloys can be considered as a good candidate, due to its great strength and electricity performance. This review describes various properties of aluminum-iron alloys including mechanical properties and electrical conductivities, as well their relation to the Fe contents. Also, metallurgical aspects of aluminum-iron alloys, including phase diagrams, equilibrium and non-equilibriun solidification, microstructure development, and castability. The further research and development work are outlined in terms of developing aluminum-iron alloys for some potential and value-added automotive applications.

Morphological Heredity of Intermetallic Nb5Si3 Dendrites in Hypereutectic Nb-Si Based Alloys via Non-Equilibrium Solidification

For hypereutectic Nb-Si based alloys, primary Nb5Si3 phases typically grow in a faceted mode during equilibrium or near-equilibrium solidification, which damages the ductility and toughness. To address this issue, here we artificially manipulate the growth morphology of Nb5Si3 using electron beam surface melting (EBSM) and subsequent annealing treatments. Results show that such a non-equilibrium solidification pathway enables the transition from faceted growth to non-faceted dendritic growth of Nb5Si3, along with evident microstructure refinement, generation of metastable β-Nb5Si3 phases and elimination of chemical segregation. The transformation from β-Nb5Si3 to α-Nb5Si3 and Nb solid solution (Nbss) particles is triggered by the annealing treatment at 1450 °C for 5 h. Also, we find the annealing-mediated formation of inherited Nb5Si3 dendrites that maintain the dendritic morphology of the original as-solidified β-Nb5Si3 dendrites. This work thus provides a feasible routine to obtain thermally stable and refined α-Nb5Si3 dendrites in hypereutectic Nb-Si based alloys.

Analysis of solidification microstructure and cracking mechanism of a matrix high-speed steel deposited using directed-energy deposition

This study investigated the microstructure and cracking mechanism of a matrix high-speed steel fabricated by direct energy deposition. The combined effect of rapid solidification and chemical composition on microstructure and cracking mechanism during deposition were investigated. Excessive solute segregation into inter-dendritic regions due to rapid solidification caused formation of retained austenite in the inter-dendritic region and formation of α'-martensite in the dendritic region. The excess solute segregation decreased equilibrium solidification temperature and caused formation of low-melting eutectic carbides in the inter-dendritic region. These carbides increased hot-cracking susceptibility, and caused solidification cracking and liquation cracking in the inter-dendritic region. In contrast, tensile residual stress in deposited layers may have caused cold cracking in α'-martensite near the hot crack tips. Cold cracks contributed to growth of macroscopic longitudinal cracks throughout the specimen by bridging the hot cracks formed during solidification or reheating.

Observing the Effect of Grain Refinement on Crystal Growth of Al and Mg Alloys during Solidification Using In-Situ Neutron Diffraction

The present research uses in-situ neutron diffraction to examine the effect of grain refinement on grain growth during solidification of Al-5 wt.% Cu and Mg-5 wt.% Zn alloys. The alloys were grain refined through additions of Al-5Ti-1B and Zr, respectively. The in-situ neutron diffraction experiments were carried out by heating the alloys to temperatures above the liquidus and subsequently cooling in 5 or 10 °C temperature steps to temperatures below solidus, while being irradiated by thermal neutrons. With the addition of grain refiners, grain size reductions of 92% were observed for both the Al-5 wt.% Cu and Mg-5 wt.% Zn alloys. The refined and unrefined Al-5 wt.% Cu alloys contained α-Al with Al2Cu along the grain boundary regions. Differences in Al2Cu morphology were observed in the grain refined alloys. The Mg-5 wt.% Zn alloy contained MgZn intermetallic phases with primary Mg. The refined Mg-5 wt.% Zn-0.7 wt.% Zr alloy contained Mg, MgZn and Zn2Zr phases. In-situ neutron diffraction enabled quantification of individual plane solid fraction growth for the α-Al and Al2Cu phases in the Al-Cu alloys, and for α-Mg in the Mg alloys. For the unrefined Al-5 wt.% Cu, the coarse microstructure resulted in a rapid solid fraction rise at temperatures just below liquidus followed by a gradual increase in solid fraction until the sample was fully solid. The grain-refined Al-5 wt.% Cu alloys showed a columnar to equiaxed microstructure transition and a more gradual growth in fraction solid throughout solidification. For the Mg-5 wt.% Zn alloy, the more packed (0002) and (101¯1) α-Mg plane intensities grew at a slower rate than the (101¯0) plane intensity, resulting in an irregular grain structure. With the addition of the Zr grain refiner, the Mg-5 wt.% Zn-0.7 wt.% Zr alloy had (101¯0), (0002) and (101¯1) planes intensities all increasing at similar rates, especially at the early stages of solidification. FactSage™ (version 6.4, Montréal, QC, Canada) equilibrium solidification models followed the fraction solid curves developed by tracking the fastest growing planes of the Mg alloys.