Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer’s process. It comprises of oxides of iron, titanium, aluminum and silica along with some other minor constituents. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud management issues for example of utilization, storage and disposal. Different avenues of red mud utilization are more or less known but none of them have so far proved to be economically viable or commercially feasible. It is generally agreed that resistance to wear of MMCs is created by reinforcement and also the wear properties are improved remarkably by introducing hard intermetallic compound into the aluminium matrix.
The reinforcing materials are generally SiC, Al2O3, TiB2 etc and are costly. The present research work has been undertaken with an objective to explore the use of red mud as a reinforcing material as a low cost option. This is due to the fact that red mud alone contains all these reinforcement elements and is plentifully available. Composites are prepared by liquid melt metallurgy techniques using vortex method. Castings are cut, turned and shaped into the required size to prepare the specimens for evaluation of the mechanical properties like hardness, tensile and wear properties.
Table of Contents
1 INTRODUCTION
1.1 COMPOSITE MATERIALS
1.2 METAL MATRIX COMPOSITES
1.3 INTRODUCTION TO ALUMINIUM ALLOYS
2 OBJECTIVES OF PROJECT
3 LITERATURE SURVEY
4 METHODOLOGY
4.1 PROCESS FLOW CHART
4.2 SIEVE OF REDMUD
4.3 STIR CASTING
5 TESTING
5.1 MICROSTRUCTURE ANALYSIS
5.2 BRINELL HARDNESS ESTIMATION
5.3 TENSILE STRENGTH ESTIMATION
5.4 WEAR
5.5 TESTS CONDUCTED ON CASTED SAMPLE PIECES
6 RESULTS AND DISCUSSIONS
6.1 MICROSTRUCTURE
6.2 HARDNESS TEST RESULTS
6.3 TENSILE TEST REULTS
6.4 WEAR TEST REULTS
7 CONCLUSIONS AND SCOPE OF FUTURE WORK
7.1 CONCLUSION
7.2 SCOPE OF FUTURE WORK
Research Objectives and Thematic Focus
This work aims to evaluate the experimental performance of aluminium-based metal matrix composites (MMCs) reinforced with red mud particles. The primary research goal is to develop a standardized stir casting process for these composites and to systematically analyze how varying weight percentages of red mud (2%, 4%, 8%, and 14%) influence the material's mechanical and tribological properties, specifically focusing on microstructure, hardness, tensile strength, and wear resistance.
- Fabrication of aluminium 6061-red mud composites using the liquid metallurgy stir casting technique.
- Evaluation of the dispersion and distribution of red mud particles within the aluminium matrix through microstructural analysis.
- Measurement and assessment of mechanical characteristics, including Brinell hardness and ultimate tensile strength.
- Investigation of wear behavior and wear rate under dry sliding conditions to determine the efficacy of red mud as a reinforcing agent.
Excerpt from the Book
1.3.3.1 RED MUD AS REINFORCEMENT
Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer’s process. It comprises of oxides of iron, titanium, aluminium and silica along with some other minor constituents. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud(refer Figure 1-2) management issues i.e. of utilization, storage and disposal. Different avenues of red mud utilization are more or less known but none of them have so far proved to be economically viable or commercially stable.
In India, about 4.71 million produced which is 6.25% of world’s total generation. It is the insoluble product after bauxite digestion with sodium hydroxide at elevated temperature and pressure. It is a mixture of compounds originally present in the parent mineral bauxite and of compounds formed or introduced during the Bayer cycle. It is disposed as slurry having a solid concentration in the range of 10-30%, pH in the range of 10-13 and high ionic strength.
Summary of Chapters
1 INTRODUCTION: Provides an overview of composite materials, metal matrix composites, and aluminium alloys, establishing the context for the research.
2 OBJECTIVES OF PROJECT: Outlines the core goals, including the development of a stir casting process and the analysis of the mechanical and wear properties of the composites.
3 LITERATURE SURVEY: Reviews existing research on aluminium-based metal matrix composites and the use of various ceramic reinforcements and industrial wastes.
4 METHODOLOGY: Details the experimental procedure, covering material preparation, sieve analysis of red mud, and the stir casting process.
5 TESTING: Describes the testing protocols used, including microstructure analysis, Brinell hardness estimation, tensile strength testing, and wear testing methods.
6 RESULTS AND DISCUSSIONS: Presents and analyzes the experimental data regarding the microstructure, hardness, tensile strength, and wear test results for varying red mud percentages.
7 CONCLUSIONS AND SCOPE OF FUTURE WORK: Summarizes the findings of the study and suggests directions for future research in composite manufacturing and treatment.
Keywords
Metal Matrix Composites, Aluminium Alloy 6061, Red Mud, Stir Casting, Reinforcement, Mechanical Properties, Hardness, Tensile Strength, Wear Resistance, Tribology, Microstructure, Material Science, Industrial Waste, Composite Fabrication, Material Testing.
Frequently Asked Questions
What is the primary focus of this research?
The research focuses on the experimental evaluation of aluminium 6061-based metal matrix composites reinforced with varying weight percentages of red mud, an industrial waste byproduct.
What is the main objective of the study?
The main objective is to develop a standardized stir casting process and investigate how the addition of red mud particles affects the hardness, tensile strength, and wear properties of the resulting composites.
Which fabrication method is employed?
The study uses the liquid metallurgy technique, specifically the stir casting method, to incorporate the red mud particles into the molten aluminium 6061 matrix.
What are the key mechanical properties evaluated?
The study evaluates microstructure, Brinell hardness, tensile strength, and wear resistance under dry sliding conditions.
How is the reinforcement prepared before casting?
The raw red mud is subjected to sieve analysis using a vibrator to ensure the particles are within the size range of 0 to 150 microns.
What specific test is used to measure wear?
A pin-on-disc machine is used to conduct dry sliding wear tests on the cast samples to determine wear rates.
How does the increase in red mud percentage affect the hardness of the composite?
The results indicate that increasing the red mud percentage leads to a decrease in hardness, as the material becomes more ductile compared to lower percentage composites.
What is the effect of red mud on the wear rate of the composite?
The study demonstrates that increasing the red mud composition from 2% to 14% significantly reduces the wear rate by approximately 77%, thereby improving the wear resistance of the material.
Is the tensile strength of the composite significantly affected by the red mud content?
The research found that the ultimate tensile strength remains relatively stable, varying around 68 N/mm², despite changes in the red mud reinforcement percentage.
What potential application does this study suggest for red mud?
The study suggests that red mud, which is a major waste product from the Bayer process, can be successfully utilized as a reinforcing material in the production of metal matrix composites.
- Quote paper
- Lokesh K S (Author), 2018, A Characterisation of Al6061 RedMud Composite, Munich, GRIN Verlag, https://www.grin.com/document/452983
