Nickel particles were embedded into an Al matrix by friction stir processing (FSP) to produce metal particle reinforced composite. FSP resulted in uniform dispersion of nickel particles with excellent interfacial bonding with the Al matrix and also lead to significant grain refinement of the matrix. The novelty of the process is that the composite was processed in one step without any pretreatment being given to the constituents and no harmful intermetallic formed. The novel feature of the composite is that it shows a three fold increase in the yield strength while appreciable amount of ductility is retained. The hardness also improved significantly. The fracture surface showed a ductile failure mode and also revealed the superior bonding between the particles and the matrix. Electron backscattered diffraction (EBSD) and transmission electron microscopy analysis revealed a dynamically recrystallized equiaxed microstructure. A gradual increase in misorientation from sub-grain to high-angle boundaries is observed from EBSD analysis pointing towards a continuous type dynamic recrystallization mechanism. © 2010 Elsevier B.V.

Ranjit Bauri

Department of Metallurgical and Materials Engineering

ALUMINIUM MATRIX COMPOSITES

Composites

DUCTILE FAILURES

EBSD

EBSD ANALYSIS

Electron back-scattered diffraction

EQUIAXED MICROSTRUCTURES

Fracture surfaces

Friction stir processing

High angle boundaries

Interfacial bonding

matrix

Mechanical characterizations

METAL PARTICLE

Microstructure and mechanical properties

Mis-orientation

NICKEL PARTICLES

ONE STEP

PRE-TREATMENT

RECRYSTALLIZATION MECHANISMS

Thermo-mechanical processing

Transmission electron

UNIFORM DISPERSIONS

Yield strength

Bonding

Ductile fracture

Dynamic recrystallization

Electrons

Grain refinement

Grain size and shape

Mechanical properties

Metallic matrix composites

microstructure

Nickel

Plastic flow

Transmission electron microscopy

PARTICLE REINFORCED COMPOSITES

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Science and Engineering A

The disposal of used automobiles tyres is a major environmental concern of the day. Annually, there are 1.2 billion tyres seeking disposal issues globally. Concrete as a major construction material can potentially adopt processed rubber waste—derived from tyres as a partial replacement for aggregates. The present study is focused on mechanical and thermal properties of concretes with rubber as partial replacement to well-graded conventional aggregates. The study includes replacement of 10, 20, 30 and 100% of coarse aggregate with waste tyre aggregates and was compared with conventional M30 grade concrete. Concretes were subjected a thermal cyclic heating of 50 °C for a period of 7 days. The results showed that the weight of the rubber concrete is reduced by 12% compared to the conventional concrete and the strength of the concrete reduces with the increase in rubber content. At ambient temperatures, the rubber concrete was found thermally stable. The compressive strengths were found increasing after cyclic heating of 50 °C for a period of 7 days. This effect may be due the effect of Portland pozzolana cement which has 30% of fly ash in it. From this study, it can be concluded that rubber waste concretes can be a potential candidate for structural and non-load bearing structures at ambient temperatures. © 2019, Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

On Mechanical and Thermal Properties of Concretes with Rubber as Partial Replacement to Well-Graded Conventional Aggregates

The present investigation shows that alternate to the ceramic particles, hard metallic particles can be used as reinforcement in an aluminum matrix to achieve a good strength–ductility combination in a composite. Titanium particles were incorporated into aluminum by friction stir processing (FSP) to process an Al-Ti particulate composite. FSP led to uniform distribution of the particles in the stir zone without any particle–matrix reaction, thereby retaining the particles in their elemental state. Fracture and twinning of the Ti particles with different frequency of occurrence on the advancing and retreating sides of the stir zone was observed. Twinning of the particles was studied by focused ion beam-assisted transmission electron microscopy. The processed Al-Ti composite exhibited a significant improvement in strength and also retained appreciable amount of ductility. The thermal stability of the fine-grained structure against abnormal grain growth (AGG) was improved by the Ti particles. The AGG in the Al-Ti composite occurred at 713 K (440 °C) compared to 673 K (400 °C) in the unreinforced aluminum processed under the same conditions. On the other hand, the particle–matrix reaction occurred only at 823 K (550 °C), and hence the Ti particles were thermally more stable compared to the matrix grain structure. © 2016, The Minerals, Metals & Materials Society and ASM International.

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Al-Ti Particulate Composite: Processing and Studies on Particle Twinning, Microstructure, and Thermal Stability

Friction stir processing (FSP) was used to incorporate tungsten particles in 5083 Al matrix to fabricate metal particle reinforced surface composites. The particles were uniformly dispersed in the matrix and the grain size was also refined by FSP. X-Ray diffraction analysis showed no intermetallic peak confirming that the tungsten particles remained in their elemental form. The composite surface layer exhibited considerably higher wear resistance compared to the base and friction stir processed (FSPed) alloy. The worn surface analysis revealed that the composite undergoes adhesive and oxidative type of mild wear at all the three loads whereas there was a transition to abrasive and delamination type of severe wear at higher loads in the base and FSPed samples. © 2016 Elsevier Ltd. All rights reserved.

Tribology International

Wear properties of 5083 Al-W surface composite fabricated by friction stir processing

Friction deposition is one of the promising new techniques for additive manufacturing. In this work, an aluminum matrix composite reinforced with titanium particles was successfully friction deposited. The multi-layer composite friction deposits showed well-bonded layers, very fine grain size, and uniformly distributed titanium particles. While the reinforcement/matrix interfaces showed no reaction products, the layer interfaces showed thin intermetallic bands. These brittle intermetallic bands were found to strongly affect the ductility of the multi-layer composite friction deposits in the build direction. However, the composite friction deposits performed satisfactorily in compression tests as well as in single-layer tensile tests. © 2015 Elsevier B.V.

Friction deposition of titanium particle reinforced aluminum matrix composites

Copper particles were incorporated and retained in elemental state in an aluminium matrix by friction stir processing thereby producing a non-equilibrium particulate composite. The processed Al-Cup composite exhibited improved strength with significantly high ductility. The composite was stable up to a temperature of more than 300uC. Thermal exposure at 350uC for more than 10 min led to diffusion of Cu atoms into the Al matrix forming a core-shell type structure in the Cu particles and thus producing an Al-Cu core-shell composite. The shell consists of multiple layers, the thickness of which was controllable. © 2015 Institute of Materials, Minerals and Mining

Materials Science and Technology (United Kingdom)

Development of Cu particles and Cu core-shell particles reinforced Al composite

Nickel particulate reinforced aluminium matrix composite was processed without formation of deleterious Al3Ni intermetallic by friction stir processing (FSP). FSP resulted in uniform dispersion of nickel particles in the aluminium matrix with excellent interfacial bonding and also lead to grain refinement of the matrix. The composite exhibited a threefold increase in the yield stress (0.2% proof stress). The most novel feature of the composite is that an appreciable amount of ductility is retained while the strength increases significantly. The microstructure evolution was studied by transmission electron microscopy and electron backscattered diffraction analysis. EBSD analysis showed a dynamically recrystallized equiaxed microstructure having a considerable fraction of low-angle boundaries. TEM observations revealed that these low-angle boundaries are essentially subgrain boundaries formed by dislocation rearrangement and absorption during friction stir processing. © 2009 Elsevier B.V. All rights reserved.

Materials Letters

Nickel particle embedded aluminium matrix composite with high ductility

Composites Part A: Applied Science and Manufacturing

Improving mechanical performance of Al by using Ti as reinforcement

Intermetallic-reinforced aluminum matrix composites produced in situ by friction stir processing

Acta Materialia

Al–Al3Ti nanocomposites produced in situ by friction stir processing

Materials Science and Engineering: A

Effect of friction stir processing on the microstructure of cast A356 aluminum

Processing, microstructure and mechanical properties of nickel particles embedded aluminium matrix composite

Journal	Materials Science and Engineering A
ISSN	09215093
Open Access	No