{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T18:53:57Z","timestamp":1773255237982,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,5,28]],"date-time":"2021-05-28T00:00:00Z","timestamp":1622160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["PD\/BD\/143030\/2018"],"award-info":[{"award-number":["PD\/BD\/143030\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>The strengthening effect of carbon nanotubes (CNTs) in metal matrix nanocomposites occurs due to several mechanisms that act simultaneously. The possible strengthening mechanisms for metal matrix nanocomposites reinforced with CNTs consist of: (1) load transfer, (2) grain refinement and texture strengthening, (3) second phase strengthening, and (4) strain hardening. The main focus of this work is to identify the strengthening mechanisms that play a role in the case of the Ni-CNT nanocomposite produced by powder metallurgy. For the dispersion and mixing of the metallic powders with CNTs, two different routes were performed by ultrasonication and ball milling. The results indicated that four different strengthening mechanisms are present in the nanocomposites and had a different contribution to the final mechanical properties. The load transfer and the increase in dislocation density seem to strongly affect the properties and microstructure of the nanocomposite. The grain refinement and the presence of second phase particles have a small contribution in the strengthening of this nanocomposite, since the introduction of CNTs in the Ni matrix slightly affects the size and orientation of the grains in the matrix and a few nanometric particles of Ni3C were identified.<\/jats:p>","DOI":"10.3390\/nano11061426","type":"journal-article","created":{"date-parts":[[2021,5,31]],"date-time":"2021-05-31T01:51:37Z","timestamp":1622425897000},"page":"1426","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Investigation on the Strengthening Mechanisms of Nickel Matrix Nanocomposites"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4798-556X","authenticated-orcid":false,"given":"\u00cdris","family":"Carneiro","sequence":"first","affiliation":[{"name":"DEMM, Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LAETA\/INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3692-585X","authenticated-orcid":false,"given":"Jos\u00e9 Valdemar","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Engineering, Materials and Processes, (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Lu\u00eds Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4670-4516","authenticated-orcid":false,"given":"S\u00f3nia","family":"Sim\u00f5es","sequence":"additional","affiliation":[{"name":"DEMM, Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LAETA\/INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,28]]},"reference":[{"key":"ref_1","first-page":"152","article-title":"Properties of cast aluminum alloys","volume":"Volume 2","author":"Kearney","year":"1990","journal-title":"Properties and Selection: Nonferrous Alloys and Special- Purpose Materials"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"935","DOI":"10.1016\/j.matdes.2010.08.006","article-title":"Precipitation hardening of cast Zr-containing A356 aluminium alloy","volume":"32","author":"Baradarani","year":"2011","journal-title":"Mater. Des."},{"key":"ref_3","unstructured":"Clyne, T.W., and Withers, P.J. (1995). An Introduction to Metal Matrix Composites, Cambridge University Press."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6153","DOI":"10.1023\/B:JMSC.0000043583.47148.31","article-title":"Review of recent studies in magnesium matrix composites","volume":"39","author":"Ye","year":"2004","journal-title":"J. Mater. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Fridlyander, J. (1995). Metal Matrix Composites, Springer.","DOI":"10.1007\/978-94-011-1266-6"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1016\/j.carbon.2013.12.089","article-title":"Grain growth analysis of multiwalled carbon nanotube-reinforced bulk Ni composites","volume":"70","author":"Lechthaler","year":"2014","journal-title":"Carbon"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1017\/S1431927618015064","article-title":"Microstructural characterization of carbon nanotubes (CNTs)-reinforced nickel matrix nanocomposites","volume":"25","author":"Carneiro","year":"2019","journal-title":"Microsc. Microanal."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Sim\u00f5es, S., Viana, F., Reis, M.A.L., and Vieira, M.F. (2017). Aluminum and nickel matrix composites reinforced by CNTs: Dispersion\/mixture by ultrasonication. Metals, 7.","DOI":"10.3390\/met7070279"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1016\/j.carbon.2013.04.105","article-title":"A combination of ball milling and high-ratio differential speed rolling for synthesizing carbon nanotube\/copper composites","volume":"61","author":"Yoo","year":"2013","journal-title":"Carbon"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.compositesb.2018.02.033","article-title":"Strength and failure mechanisms of CNT-reinforced copper nanocomposite","volume":"145","author":"Faria","year":"2018","journal-title":"Compos. Part B Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1800422","DOI":"10.1002\/adem.201800422","article-title":"Influence of processing parameters on the mechanical properties of HPT-deformed nickel\/carbon nanotube composites","volume":"21","author":"Katzensteiner","year":"2019","journal-title":"Adv. Eng. Mater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.msea.2018.03.007","article-title":"Microstructure and strength of nano-\/ultrafine-grained carbon nanotube-reinforced titanium composites processed by high-pressure torsion","volume":"722","author":"Li","year":"2018","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.jma.2017.12.003","article-title":"An investigation on the hardness and corrosion behavior of MWCNT\/Mg composites and grain refined Mg","volume":"6","author":"Saikrishna","year":"2018","journal-title":"J. Magnes. Alloy."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/j.jmrt.2018.03.005","article-title":"Al-MWCNT nanocomposite synthesized via spark plasma sintering: Effect of powder milling and reinforcement addition on sintering kinetics and mechanical properties","volume":"8","author":"Singh","year":"2019","journal-title":"J. Mater. Res. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.1016\/j.jallcom.2018.09.165","article-title":"Surface mechanical properties of shot-peened CNT\/Al\u2013Mg\u2013Si alloy composites","volume":"773","author":"Zhu","year":"2019","journal-title":"J. Alloys Compd."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1016\/j.msea.2019.04.093","article-title":"Tailoring and characterization of carbon nanotube dispersity in CNT\/6061Al composites","volume":"757","author":"Chen","year":"2019","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.compositesa.2018.08.010","article-title":"CNT-reinforced metal and steel nanocomposites: A comprehensive assessment of progress and future directions","volume":"114","author":"Radhamani","year":"2018","journal-title":"Compos. Part A Appl. Sci. Manuf."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Tjong, S.C. (2009). Mechanical characteristics of carbon nanotube\u2013metal nanocomposites. Carbon Nanotube Reinforced Composites, Wiley-VCH Verlag GmbH & Co. KGaA.","DOI":"10.1002\/9783527626991"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.diamond.2018.06.026","article-title":"Enhancing the strength of carbon nanotubes reinforced copper matrix composites by optimizing the interface structure and dispersion uniformity","volume":"88","author":"Chen","year":"2018","journal-title":"Diam. Relat. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1016\/j.carbon.2015.08.061","article-title":"Rapid and low temperature spark plasma sintering synthesis of novel carbon nanotube reinforced titanium matrix composites","volume":"95","author":"Wang","year":"2015","journal-title":"Carbon"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"152303","DOI":"10.1016\/j.jallcom.2019.152303","article-title":"High strength and high ductility in nickel matrix nanocomposites reinforced by carbon nanotubes and onion-like-carbon hybrid reinforcements","volume":"814","author":"Wen","year":"2020","journal-title":"J. Alloys Compd."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.carbon.2013.11.061","article-title":"Direct observation of carbon nanotube induced strengthening in aluminum composite via in situ tensile tests","volume":"69","author":"Boesl","year":"2014","journal-title":"Carbon"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.compscitech.2015.03.009","article-title":"Load transfer strengthening in carbon nanotubes reinforced metal matrix composites via in-situ tensile tests","volume":"113","author":"Chen","year":"2015","journal-title":"Comp. Sci. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"8655","DOI":"10.1007\/s10853-019-03411-0","article-title":"Carbon nanotube-reinforced aluminum matrix composites enhanced by grain refinement and in situ precipitation","volume":"54","author":"Xu","year":"2019","journal-title":"J. Mater. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"570","DOI":"10.1016\/j.carbon.2008.10.041","article-title":"Combination of hot extrusion and spark plasma sintering for producing carbon nanotube reinforced aluminum matrix composites","volume":"47","author":"Kwon","year":"2009","journal-title":"Carbon"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1088\/0957-4484\/17\/1\/002","article-title":"Development of novel carbon nanotube reinforced magnesium nanocomposites using the powder metallurgy technique","volume":"17","author":"Goh","year":"2006","journal-title":"Nanotechnology"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.msea.2006.04.085","article-title":"Microstructures and tensile behavior of carbon nanotube reinforced Cu matrix nanocomposites","volume":"430","author":"Kim","year":"2006","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"154075","DOI":"10.1016\/j.jallcom.2020.154075","article-title":"Mechanical properties and strain hardening behavior of aluminum matrix composites reinforced with few-walled carbon nanotubes","volume":"826","author":"Chen","year":"2020","journal-title":"J. Alloys Compd."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Carneiro, \u00cd., Viana, F., Vieira, F.M., Fernandes, V.J., and Sim\u00f5es, S. (2019). EBSD analysis of metal matrix nanocomposite microstructure produced by powder metallurgy. Nanomaterials, 9.","DOI":"10.3390\/nano9060878"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Zouari, M., Log\u00e9, R., and Bozzolo, N. (2017). In Situ Characterization of inconel 718 post-dynamic recrystallization within a scanning electron microscope. Metals, 7.","DOI":"10.3390\/met7110476"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Hadadzadeh, A., Mokdad, F., Wells, M., and Chen, D.L. (2018). A new grain orientation spread approach to analyze the dynamic recrystallization behavior of a cast-homogenized Mg-Zn-Zr alloy using electron backscattered diffraction. Mater. Sci. Eng. A, 285\u2013289.","DOI":"10.1016\/j.msea.2017.10.062"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"316","DOI":"10.1017\/S1431927611000055","article-title":"A review of strain analysis using electron backscatter diffraction","volume":"17","author":"Wright","year":"2011","journal-title":"Microsc. Microanal."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.scriptamat.2014.03.008","article-title":"Formation of annealing twin boundaries in nickel","volume":"81","author":"Bair","year":"2014","journal-title":"Scr. Mater."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"4187","DOI":"10.1016\/S1359-6454(99)00277-3","article-title":"Mechanism of twinning-induced grain boundary engineering in low stacking-fault energy materials","volume":"47","author":"Randle","year":"1999","journal-title":"Acta Mater."},{"key":"ref_35","unstructured":"Beausir, B., and Fundengerger, J.-J. (2017). Analysis Tools for Electron and X-ray Diffraction, ATEX\u2014Software, Universit\u00e9 of Lorraine. Available online: www.atex-software.eu."},{"key":"ref_36","unstructured":"Agarwal, A., Bakshi, S.R., and Lahiri, D. (2011). Carbon Nanotubes: Reinforced Metal Matrix Composites, CRC Press."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Carneiro, \u00cd., and Sim\u00f5es, S. (2020). Effect of morphology and structure of MWCNTs on metal matrix nanocomposites. Materials, 13.","DOI":"10.3390\/ma13235557"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1021\/nl052356k","article-title":"Direct observation of single-walled carbon nanotube growth at the atomistic scale","volume":"6","author":"Lin","year":"2006","journal-title":"Nano Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"6387","DOI":"10.1063\/1.1728293","article-title":"The role of the catalytic particle in the growth of carbon nanotubes by plasma enhanced chemical vapor deposition","volume":"95","author":"Ducati","year":"2004","journal-title":"J. Appl. Phys."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2042","DOI":"10.1016\/j.ceramint.2017.10.149","article-title":"Synthesis and characterization of in-situ CNTs reinforced TiB2-based composite by CVD using Ni catalysts","volume":"44","author":"Lin","year":"2018","journal-title":"Ceram. Int."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"2779","DOI":"10.1088\/0022-3727\/35\/21\/314","article-title":"Carbon nanotubes deposition in glow barrier discharge enhanced catalytic CVD","volume":"35","author":"Nozaki","year":"2002","journal-title":"J. Phys. D Appl. Phys."}],"container-title":["Nanomaterials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-4991\/11\/6\/1426\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:09:51Z","timestamp":1760162991000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-4991\/11\/6\/1426"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,5,28]]},"references-count":41,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,6]]}},"alternative-id":["nano11061426"],"URL":"https:\/\/doi.org\/10.3390\/nano11061426","relation":{},"ISSN":["2079-4991"],"issn-type":[{"value":"2079-4991","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,5,28]]}}}