The present work is focused on the study of the effect of directional heat extraction on the silicon-carbide (SiC) distribution in zinc-aluminum matrix composites (MMCs) and on the columnar-to-equiaxed (CET) position in directionally solidified samples. To this end, a ZA-27 alloy matrix was reinforced with ceramic particles of SiC and vertically directionally solidified. The cooling rates, temperature gradients, and interphase velocities were then measured, and their influence on the solidification microstructure of the MMCs was analyzed. The recalescence detected and measured during the equiaxed transition was of the order of 3.5&#xb0;C to 1.1&#xb0;C. The values of the temperature gradients reached a minimum during the CET and were even negative in most cases (between &#x2212;3.89&#x2009;K and 0.06&#x2009;K). The interphase velocities varied between 0.07&#x2009;mm/s and 0.44&#x2009;mm/s at the transition. Also, the presence of ceramic particles in ZA-27 alloys affected the thermodynamic local conditions and the kinetics of nucleation, producing a finer microstructure.

Alicia E. Ares

Carlos E. Schvezov

Columnar-to-Equiaxed Transition in Metal-Matrix Composites Reinforced with Silicon Carbide Particles

Factorial analysis of heat affected zone hardness of some metals was evaluated. Three models were derived and used as tools for evaluating the welding current influence on the predictability of HAZ hardness in aluminium, cast iron, and mild steel weldments similarly cooled in palm oil. It was discovered that on welding these materials, and similarly cooling their respective weldments in palm oil, the model <svg     style="vertical-align:-5.76988pt;width:310.32501px;" id="M1" height="23.025" version="1.1" viewBox="0 0 310.32501 23.025" width="310.32501"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,15.775)"><path id="x1D6FC" d="M545 106q-67 -118 -134 -118q-24 0 -40 37.5t-30 129.5h-2q-47 -72 -103 -119.5t-108 -47.5q-47 0 -76 45.5t-29 119.5q0 113 85 204t174 91q47 0 70 -33.5t43 -119.5h3q32 47 80 140l55 13l10 -9q-47 -80 -138 -201q17 -99 27.5 -136t22.5 -37q23 0 69 61zM333 204&#xA;q-14 98 -31 149.5t-50 51.5q-49 0 -94 -70t-45 -164q0 -55 15.5 -86t40.5 -31q70 0 164 150z" /></g>

			<g transform="matrix(.012,-0,0,-.012,9.712,19.862)"><path id="x1D464" d="M689 332q0 -81 -40 -161.5t-103.5 -131.5t-127.5 -51q-32 0 -58.5 16t-40.5 46q-70 -62 -139 -62q-45 0 -77.5 30t-32.5 86q0 8 7 52q11 77 45 187q6 19 6 34q0 6 -7 6q-24 0 -78 -64l-20 23q32 48 73 77t78 29q32 0 32 -43q0 -30 -12 -73q-27 -95 -38 -152&#xA;q-8 -44 -8 -58q0 -77 68 -77q31 0 60 33.5t39 77.5l62 260l75 16l5 -6l-63 -246q-8 -29 -8 -58q0 -77 68 -77q66 0 116 75.5t50 194.5q0 43 -12 57q-11 12 -11 24q0 19 15 35.5t34 16.5q18 0 30.5 -34.5t12.5 -81.5z" /></g>

			<g transform="matrix(.017,-0,0,-.017,23.537,15.775)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,38.224,15.775)"><path id="x28" d="M300 -147l-18 -23q-106 71 -159 185.5t-53 254.5v1q0 139 53 252.5t159 186.5l18 -24q-74 -62 -115.5 -173.5t-41.5 -242.5q0 -130 41.5 -242.5t115.5 -174.5z" /></g><g transform="matrix(.017,-0,0,-.017,44.106,15.775)"><path id="x1D6FE" d="M478 372q0 -39 -31 -97t-61 -98t-78 -98q-45 -55 -73 -102q-13 -79 -13 -197q-11 -11 -43.5 -25.5t-53.5 -15.5l-15 17q5 35 26 101.5t47 123.5q8 72 -1.5 174.5t-37.5 178.5q-14 37 -29 37q-20 0 -67 -65l-25 21q37 60 73 90.5t63 30.5q47 0 72 -112q13 -56 17.5 -141.5&#xA;t0.5 -143.5h2q155 193 155 297q0 26 -12 47q-5 8 -5 15q0 16 12.5 27t29.5 11q21 0 34 -21t13 -55z" /></g>

			<g transform="matrix(.012,-0,0,-.012,52.638,20.812)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,61.725,15.775)"><path id="x1D6FD" d="M558 587q0 -32 -14 -61t-40 -53.5t-48.5 -41t-54.5 -36.5q144 -51 144 -174q0 -55 -43.5 -108t-104.5 -87q-77 -42 -131 -42q-31 0 -54 20t-31 47l11 18q48 -29 108 -29q79 0 119.5 43t40.5 109t-44.5 107.5t-119.5 50.5l22 47q34 1 65 21q96 61 96 157q0 42 -24 67.5&#xA;t-62 25.5q-24 0 -43.5 -9t-35 -29.5t-27 -44t-22.5 -63t-19.5 -75.5t-18.5 -91q-57 -294 -68 -380q-26 -190 -35 -200q-26 -31 -97 -37l-4 26q19 9 48 170l77 413q23 121 52.5 187.5t83.5 114.5q70 62 148 62q51 0 88.5 -34t37.5 -91z" /></g>

			<g transform="matrix(.012,-0,0,-.012,71.6,20.812)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,80.7,15.775)"><path id="x2F" d="M368 703l-264 -866h-60l265 866h59z" /></g><g transform="matrix(.017,-0,0,-.017,87.703,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,93.585,15.775)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.012,-0,0,-.012,103.462,20.812)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,116.337,15.775)"><path id="x2B" d="M535 230h-212v-233h-58v233h-213v50h213v210h58v-210h212v-50z" /></g><g transform="matrix(.017,-0,0,-.017,130.072,15.775)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.012,-0,0,-.012,138.6,20.812)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,147.7,15.775)"><path id="x29" d="M275 270q0 -296 -211 -440l-19 23q75 62 116.5 174t41.5 243t-42 243t-116 173l19 24q211 -144 211 -440z" /></g><g transform="matrix(.017,-0,0,-.017,153.582,15.775)"><use xlink:href="#x29"/></g><g transform="matrix(.017,-0,0,-.017,159.463,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,165.345,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,171.226,15.775)"><path id="x1D456" d="M244 607q0 -25 -15.5 -43t-37.5 -18q-19 0 -32 13t-13 35q0 21 15 41t39 20q20 0 32 -14t12 -34zM222 91q-29 -33 -79 -68t-75 -35q-13 0 -19 7.5t-6 31t10 65.5l62 253q5 26 -1 26q-21 0 -72 -43l-13 24q43 40 91 68t71 28q30 0 10 -78l-71 -274q-8 -30 3 -30&#xA;q16 0 76 48z" /></g>

			<g transform="matrix(.012,-0,0,-.012,175.862,19.862)"><use xlink:href="#x1D6FC"/></g>

			<g transform="matrix(.017,-0,0,-.017,183.25,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,187.888,19.862)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.017,-0,0,-.017,199.2,15.775)"><use xlink:href="#x2B"/></g><g transform="matrix(.017,-0,0,-.017,212.952,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,217.6,19.862)"><use xlink:href="#x1D6FC"/></g>

			<g transform="matrix(.017,-0,0,-.017,224.975,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,229.625,19.862)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.017,-0,0,-.017,236.2,15.775)"><use xlink:href="#x29"/></g><g transform="matrix(.017,-0,0,-.017,242.082,15.775)"><use xlink:href="#x2F"/></g><g transform="matrix(.017,-0,0,-.017,249.085,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,253.725,19.862)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.017,-0,0,-.017,260.312,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,264.95,19.862)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.017,-0,0,-.017,272.488,15.775)"><use xlink:href="#x29"/></g>

			<g transform="matrix(.012,-0,0,-.012,278.375,7.613)"><path id="x30" d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105&#xA;q0 -76 10 -138.5t37 -107.5t69 -45q32 0 55.5 25t35.5 68.5t17.5 91.5t5.5 105t-5.5 105.5t-18 92t-36 68t-56.5 24.5z" /></g><g transform="matrix(.012,-0,0,-.012,284.086,7.613)"><path id="x2E" d="M113 -12q-24 0 -39.5 16t-15.5 42q0 24 16 40.5t40 16.5t40 -16.5t16 -40.5q0 -26 -16 -42t-41 -16z" /></g><g transform="matrix(.012,-0,0,-.012,286.799,7.613)"><path id="x38" d="M249 635q70 0 116 -43t46 -105q0 -46 -28 -80q-22 -25 -80 -64q62 -35 97 -75t35 -99q0 -81 -63 -131t-135 -50q-83 0 -137.5 45.5t-54.5 123.5q0 52 45 95q29 28 89 64q-109 62 -109 155q0 66 50.5 115t128.5 49zM238 603q-42 0 -67.5 -31t-25.5 -72q0 -50 32.5 -79.5&#xA;t98.5 -62.5q61 48 61 124q0 59 -29.5 90t-69.5 31zM248 20q46 0 76.5 33.5t30.5 89.5q0 50 -39 85.5t-110 71.5q-81 -54 -81 -137q0 -67 35.5 -105t87.5 -38z" /></g><g transform="matrix(.012,-0,0,-.012,292.511,7.613)"><path id="x34" d="M456 178h-96v-72q0 -51 12.5 -62.5t72.5 -16.5v-27h-256v27q65 5 78 17t13 62v72h-260v28q182 271 300 426h40v-407h96v-47zM280 225v295h-2q-107 -148 -196 -295h198z" /></g><g transform="matrix(.012,-0,0,-.012,298.222,7.613)"><path id="x39" d="M244 635q90 0 143 -72t53 -177q0 -133 -65 -229.5t-171 -139.5q-79 -32 -140 -32l-5 30q109 18 185 91t101 186l-68 -36q-29 -16 -60 -16q-79 0 -129 51.5t-50 130.5q0 80 57 146.5t149 66.5zM228 602q-52 0 -78 -45.5t-26 -98.5q0 -69 36.5 -115.5t97.5 -46.5&#xA;q53 0 90 28q4 31 4 66q0 51 -9.5 95.5t-39 80.5t-75.5 36z" /></g><g transform="matrix(.012,-0,0,-.012,303.934,7.613)"><use xlink:href="#x38"/></g>

		
	
</svg> predicts aluminium weldment HAZ hardness by multiplying the determined general current product rule (GCPR) <svg     style="vertical-align:-5.76988pt;width:150.925px;" id="M2" height="23.025" version="1.1" viewBox="0 0 150.925 23.025" width="150.925"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,5.944,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,11.826,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,16.463,19.862)"><use xlink:href="#x1D6FC"/></g>

			<g transform="matrix(.017,-0,0,-.017,23.85,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,28.487,19.862)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.017,-0,0,-.017,39.8,15.775)"><use xlink:href="#x2B"/></g><g transform="matrix(.017,-0,0,-.017,53.552,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,58.2,19.862)"><use xlink:href="#x1D6FC"/></g>

			<g transform="matrix(.017,-0,0,-.017,65.575,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,70.225,19.862)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.017,-0,0,-.017,76.8,15.775)"><use xlink:href="#x29"/></g><g transform="matrix(.017,-0,0,-.017,82.682,15.775)"><use xlink:href="#x2F"/></g><g transform="matrix(.017,-0,0,-.017,89.685,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,94.325,19.862)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.017,-0,0,-.017,100.913,15.775)"><use xlink:href="#x1D456"/></g>

			<g transform="matrix(.012,-0,0,-.012,105.55,19.862)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.017,-0,0,-.017,113.088,15.775)"><use xlink:href="#x29"/></g>

			<g transform="matrix(.012,-0,0,-.012,118.975,7.613)"><use xlink:href="#x30"/></g><g transform="matrix(.012,-0,0,-.012,124.686,7.613)"><use xlink:href="#x2E"/></g><g transform="matrix(.012,-0,0,-.012,127.399,7.613)"><use xlink:href="#x38"/></g><g transform="matrix(.012,-0,0,-.012,133.111,7.613)"><use xlink:href="#x34"/></g><g transform="matrix(.012,-0,0,-.012,138.822,7.613)"><use xlink:href="#x39"/></g><g transform="matrix(.012,-0,0,-.012,144.534,7.613)"><use xlink:href="#x38"/></g>

		
	
</svg> with the ratio: HAZ hardness product of cast iron and mild steel/HAZ hardness sum of cast iron and mild steel <svg     style="vertical-align:-4.15506pt;width:121.35px;" id="M3" height="17.4" version="1.1" viewBox="0 0 121.35 17.4" width="121.35"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,12.162)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,5.944,12.162)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.012,-0,0,-.012,14.462,17.2)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,23.55,12.162)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.012,-0,0,-.012,33.438,17.2)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,42.525,12.162)"><use xlink:href="#x2F"/></g><g transform="matrix(.017,-0,0,-.017,49.528,12.162)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,55.41,12.162)"><use xlink:href="#x1D6FD"/></g>

			<g transform="matrix(.012,-0,0,-.012,65.288,17.2)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,78.162,12.162)"><use xlink:href="#x2B"/></g><g transform="matrix(.017,-0,0,-.017,91.914,12.162)"><use xlink:href="#x1D6FE"/></g>

			<g transform="matrix(.012,-0,0,-.012,100.438,17.2)"><use xlink:href="#x1D464"/></g>

			<g transform="matrix(.017,-0,0,-.017,109.525,12.162)"><use xlink:href="#x29"/></g><g transform="matrix(.017,-0,0,-.017,115.407,12.162)"><use xlink:href="#x29"/></g>

		
	
</svg>. Computational analysis of experimental and model-predicted results indicates that aluminium, cast iron, and mild steel weldment HAZ hardness per unit welding current as evaluated from experiment and derived model are 3.3917, 4.8333, and 2.7944 and 3.3915, 4.8335, and 2.7946 (VHN) A<sup  >&#x2212;1</sup>, respectively. Deviational analysis shows that the maximum deviation of model-predicted HAZ hardness from the experimental results is less than 0.007&#x25;. This invariably implies over 99.99 &#x25; confidence level for the derived models.

C. I. Nwoye

J. U. Odo

E. M. Ameh

S. O. Nwakpa

Factorial Analysis of Welding Current Influence on Heat Affected Zone Hardness of Cast Iron, Aluminium, and Mild Steel Weldments Cooled in Palm Oil

Magnesium vapor reduction of niobium pentoxide was studied using a laboratory system. Niobium powder was prepared by the magnesium vapor reduction at 1123&#x2009;K for 5 hours and it contained about 8 mass &#x25; oxygen. However, the oxygen concentration could be decreased to 0.65&#x25; when it was prepared by double-step reduction by magnesium vapor and a chemical treatment. Controlled and diluted supply of magnesium vapor to the reaction front has averted excess heat generation at the reaction front and thereby fine particles were produced. Effects of various factors on the vapor reduction process were studied and discussed.

T. Satish Kumar

S. Rajesh Kumar

M. Lakshmipathi Rao

T. L. Prakash

Preparation of Niobium Metal Powder by Two-Stage Magnesium Vapor Reduction of Niobium Pentoxide

The inhibition effect of some prepared compounds, namely, thiadiazole derivatives, on N80 steel corrosion in 15% HCl solutions has been studied by using the weight loss, electrochemical polarization, and electrochemical impedance spectroscopy techniques. It was found that the inhibition efficiency of the thiadiazole derivatives, namely, 2-amino-5-(4-methoxyphenyl)-1,3,4-thiazole (AMPT), 2-amino-5-phenyl-1,3,4-thiazole (APT), and 2-amino-5-(4-chlorophenyl)-1,3,4-thiazole (ACPT), increases with the increase in concentration. Inhibition efficiency follows the order AMPT > APT > ACPT. The effect of temperature on the corrosion was investigated by the weight loss method, and some thermodynamic parameters were calculated. The inhibitive action may be attributed to the adsorption of inhibitor molecules on the active sites of the metal surface following Langmuir adsorption isotherm. Polarization measurements indicated that thiadiazole derivatives act as mixed-type corrosion inhibitor. The adsorption of thiadiazole derivatives on N80 surface exposed to inhibitor-containing solutions was confirmed using SEM and FT-IR spectra.

M. Yadav

Sumit Kumar

Debasis Behera

[Retracted] Inhibition Effect of Substituted Thiadiazoles on Corrosion Activity of N80 Steel in HCl Solution

A less magnitude of liquid aluminum deformation is required to shorten the anode-cathode distance so as to lower the electric energy consumption of the aluminum reduction cell. A mathematical model aimed to describe the electrolyte/aluminum two-phase flow in reduction cells, based on the computational fluid dynamics method, was developed to study the impacts of the cathode convexes on the electrolyte/aluminum interface deformation. The results showed that the magnitude of the two-phase interface deformation was reduced for about 17.2&#x25; with the novel cathode convexes; while at the same time, the washout of the melt on the ledge was also enhanced.

Z. He

T. Xia

W. Xiong

Q. Shen

B. Li

Mathematical Models for the Novel Cathode Convexes in a Reduction Cell

A unique study of structural and chemical analysis of crystalline phases in developed agglomerated fluxes was carried out. Thirty-two fluxes were developed by using a mixture of oxides, halides, carbonates, silicates, and ferroalloys for submerged arc welding. The present paper focuses on only ten (out of thirty-two) fluxes which were analyzed by X-ray diffraction (XRD) to know the different types of oxides formed and changed in oxidation number of metallic centers after sintering process at around 850<sup>&#x2218;</sup>C. To know the effect of temperature over phase transformation and melting of different compounds, differential thermal analysis (DTA) was carried out from 1000 to 1400<sup>&#x2218;</sup>C. This study aims to know the quantity of ions present (percentage) and melting behavior of developed agglomerated fluxes for submerged arc welding process.

Ajay Kumar

Hari Singh

Sachin Maheshwari

XRD and DTA Analysis of Developed Agglomerated Fluxes for Submerged Arc Welding

About this journal

Journal profile

Meet the editorial board

Editor spotlight

Submit your proposal

Do you think there is an emerging area of research that really needs to be highlighted? Or an existing research area that has been overlooked or would benefit from deeper investigation? Raise the profile of a research area by leading a Special Issue.

Journal of Metallurgy