THE EFFECT OF AGING HEAT TREATMENT ON HARDNESS AND MECHANICAL PROPERTIES OF ALUMINIUM ALLOY NOOR MUHAMMAD JAMALLUDDIN BIN JUSOH This report submitted in partial Fulfilment of the requirements for the award of a Bachelor of Mechanical Engineering (Structure & Materials) Faculty of Mechanical Engineering Universiti Teknikal Malaysia Melaka
v ABSTRAK Dalam kajian ini, mekanisme pengagihan semula Mg dan Si atom semasa proses penuaan semula jadi telah dicadangkan. Hasil kajian ini untuk menentukan kesan penuaan rawatan pada kekerasan dan sifat-sifat mekanik Aloi Aluminium 6061 selepas Proses Rawatan Haba. Kesan penuaan semula jadi ditentukan berdasarkan perbandingan di antara medium pelindapkejutan selepas Rawatan Haba Penyelesaian dan Rawatan Penuaan dalam medium Relau dan penyejukan di Udara. Ujian bahan yang telah digunakan adalah berdasarkan kekerasan, tegangan dan analisis mikrostruktur. Tujuan ujian kekerasan adalah untuk mencari bacaan kekerasan untuk semua sampel yang digunakan untuk melihat kesan keretakan yang berlaku selepas membuat merawat proses haba untuk aloi aluminium yang 6061. Daripada ujian tegangan, tujuan adalah untuk mengetahui tenaga tegangan yang diserap untuk mematahkan sampel bahan dan kemudian membuat data perbandingan di antara sebelum dan selepas rawatan haba. Akhir sekali, untuk analisa mikrostruktur ia adalah penting untuk ditentukan kerana untuk melihat kesan proses penuaan dalam mikrostruktur aloi aluminium selepas membuat proses rawatan haba. Daripada data dan hasil yang telah ditentukan, ia menunjukkan hasil positif yang berdasarkan objektif dan skop projek ini.
vi ABSTRACT In this study, the mechanism of Mg and Si atom redistribution during the process of natural aging has been proposed. The result of this study to determine the effect of aging treatment on hardness and mechanical properties of Aluminum Alloy 6061 after Heat Treatment Process. The effect of natural aging are determined based on comparison between quenching medium after Solution Heat Treatment and Aging Treatment in medium of Furnace and cooling in Air. The material testing that had been applied is based on hardness, tensile and microstructure analysis. The purpose of the hardness testing are to find out the hardness reading for all samples that used to look fracture effect that occur after make a heat treating process to the aluminum alloy 6061. From the tensile test, the purposes are to know tensile energy that absorbed to fracture the samples of the material and then make a comparison data between after and before heat treatment. Lastly, for microstructure analysis it is important to determine because to look the effect of aging process in the microstructure of aluminum alloy after make heat treatment process. From the data and result that already determined, it shown the positive result based on the objectives and scope of this project.
TABLE OF CONTENT CHAPTER TOPIC PAGES DECLARATION DEDICATION ACKNOWLEDGEMENTS ABSTRAK ABSTRACT TABLE OF CONTENT LIST OF FIGURES LIST OF TABLES LIST OF SYMBOLS LIST OF APPENDIXS ii iii iv v vi ix xv xix xxi xxii CHAPTER 1 INTRODUCTION 1.1 Background 1 1.2 Problem Statement 2 1.3 Objectives 3 1.4 Scopes 3 1.5 Overview of the project 3
CHAPTER 2 LITERATURE REVIEW 2.1 Aluminum 4 2.2 Aluminum Alloy 6 2.3 Application of Aluminum Alloy 2.3.1 Transport 7 2.3.2 Aeronautics 7 2.3.3 Construction 8 2.3.4 Architectural Sheet 9 2.3.5 Electrical and Thermal Applications 9 2.3.6 Packaging 10 2.3.7 Domestic 10 2.4 6061 Aluminum Alloy 11 2.4.1 Aluminum Alloy Series System 11 2.4.2 Composition 12 2.4.3 Location in Periodic Table 12 2.4.4 Phase Diagram 13 2.4.5 Application 14 2.4.5.1 Dynamo Lighting System 14 2.4.5.2 Modular Crossover Platform 15 2.4.5.3 Bicycle Frame 15 2.4.5.4 Hemi Spark Plug Tubes 16 CHAPTER 3 METHODOLOGY 3.1 Flow Chart 17 3.2 Laboratory Process 18 3.3 Specimen 19
3.3.1 Shape of Specimen 19 3.3.2 Specimen Drawing 19 3.3.3 Specimen Dimensions 20 3.3.4 Quantity of Specimen 20 3.4 Process 3.4.1 Sample Preparation 21 3.4.2 CNC Lathe Machine 22 3.4.3 Heat Treatment Process 3.4.3.1 Purpose 24 3.4.3.2 Solution Heat Treatment 24 3.4.3.3 Quenching 26 3.4.4 Hardness Test 27 3.4.5 Tensile Test 28 3.4.6 Microstructure Observation 29 3.4.6.1 Microstructural 30 3.4.6.2 Diagram 30 3.4.6.3 Microscopic Examination 30 CHAPTER 4 RESULTS 4.1 Hardness Test 38 4.2 Tensile Test 40 4.3 Stress Strain 4.3.1 Stress Strain Specimen 1 42 4.3.2 Stress Strain Specimen 2 43 4.3.3 Stress Strain Specimen 3 44 4.3.4 Stress Strain Specimen 4 45 4.3.5 Stress Strain Specimen 5 46
4.3.6 Stress Strain Specimen 6 47 4.3.7 Stress Strain Specimen 7 48 4.3.8 Stress Strain Specimen 8 49 4.3.9 Stress Strain Specimen 9 50 4.3.1.0 Stress Strain Specimen 10 51 4.3.1.1 Stress Strain Specimen 11 52 4.3.1.2 Stress Strain Specimen 12 53 4.3.1.3 Stress Strain Specimen 13 54 4.3.1.4 Stress Strain Specimen 14 55 4.3.1.5 Stress Strain Specimen 15 56 4.3.1.6 Stress Strain Specimen 16 57 4.3.1.7 Stress Strain Specimen 17 58 4.3.1.8 Stress Strain Specimen 18 59 4.3.1.9 Stress Strain Specimen 19 60 4.3.2.0 Stress Strain Specimen 20 61 4.5 Microstructure Using Optical Microscope 62 CHAPTER 5 DISCUSSION 5.1 Effect of Aging Treatment on Aluminum Alloy 63 5.2 Effect of Aging Treatment in Quenching 64 5.3 Effect of Aging Treatment on Hardness 66 5.4 Effect of Aging Treatment on Mechanical 5.4.1 Ductility 69 5.4.2 Stress and Strain 69 5.4.3 Microstructure 72
CHAPTER 6 CONCLUSION 6.1 Recommendation 75 6.2 Conclusion 78 6.3 Appendix 79-91
LIST OF FIGURES NO TOPIC PAGES 1.2 Cup and Cone Aluminum Alloy Fracture 2 2.1 Element of Aluminum 5 2.2 Production 6 2.4 Sample Product 11 2.4.4 (a) Al-Mg Phase Diagram 13 2.4.4 (b) Al-Si Phase Diagram 14 3.1 Flow Chart 17 3.3.1 Specimen 19 3.3.2 Drawing 19 3.3.3 Specimen Dimension 20 3.4.1 (a) Milling Machine 21 3.4.1 (b) Cutting Material 22 3.4.2 (a) CNC Lathe Machine 22 3.4.2 (b) Shape The Specimen 23 3.4.3 Furnace 24 3.4.3.3 (a) Cooling in Air 26 3.4.3.3 (b) Cooling in Furnace 26 3.4.4 Rockwell Hardness 27 3.4.5 INSTRON Equipment 28 3.4.6 Microscope 29 3.4.6.2 Change of Microstructure 30
3.4.6.3.1 Cutting 31 3.4.6.3.2 Mounting Machine 31 3.4.6.3.3 Smooth Face 32 3.4.6.3.4 Centre The Specimen 33 3.4.6.3.5 Pour The Resin 33 3.4.6.3.6 Pressure Setting 34 3.4.6.3.7 Grinding Machine 35 3.4.6.3.8 Ultrasonic Bath 35 3.4.6.3.9 Keller s Reagent 36 4.3.1 Stress Strain Graph for Specimen 1 42 4.3.2 Stress Strain Graph for Specimen 2 43 4.3.3 Stress Strain Graph for Specimen 3 44 4.3.4 Stress Strain Graph for Specimen 4 45 4.3.5 Stress Strain Graph for Specimen 5 46 4.3.6 Stress Strain Graph for Specimen 6 47 4.3.7 Stress Strain Graph for Specimen 7 48 4.3.8 Stress Strain Graph for Specimen 8 49 4.3.9 Stress Strain Graph for Specimen 9 50 4.3.1.0 Stress Strain Graph for Specimen 10 51 4.3.1.1 Stress Strain Graph for Specimen 11 52 4.3.1.2 Stress Strain Graph for Specimen 12 53 4.3.1.3 Stress Strain Graph for Specimen 13 54 4.3.1.4 Stress Strain Graph for Specimen 14 55 4.3.1.5 Stress Strain Graph for Specimen 15 56 4.3.1.6 Stress Strain Graph for Specimen 16 57 4.3.1.7 Stress Strain Graph for Specimen 17 58 4.3.1.8 Stress Strain Graph for Specimen 18 59 4.3.1.9 Stress Strain Graph for Specimen 19 60 4.3.2.0 Stress Strain Graph for Specimen 20 61 4.4 (a) (b) For Cooling in Furnace 62 4.4 (c ) (d) For Cooling in Air 62 5.4.1 Moderately Ductile Failure 69 5.4.2 Principal of Stress Strain 70
LIST OF TABLES NO TOPIC PAGES 2.4.1 The Major Alloying Element Grouped of Aluminum 12 Alloy 2.4.2 Typical Composition of Aluminum Alloy 6061 12 2.4.3 Major Element of 6061 in Periodic Table 13 3.2 Laboratory Process 18 3.3.4 Quantity of Specimen 20 3.4.3 Specimen for Heat Treatment Process 23 3.4.4 Typical Scale Applications 28 4.1 Hardness Value for All Specimen 39 4.2 (a) Tensile Test for Cooling in Furnace 41 4.2 (b) Tensile Test for Cooling in Air 41 4.3.1 Data Stress Strain for Specimen 1 42 4.3.2 Data Stress Strain for Specimen 2 43 4.3.3 Data Stress Strain for Specimen 3 44 4.3.4 Data Stress Strain for Specimen 4 45 4.3.5 Data Stress Strain for Specimen 5 46 4.3.6 Data Stress Strain for Specimen 6 47 4.3.7 Data Stress Strain for Specimen 7 48 4.3.8 Data Stress Strain for Specimen 8 49 4.3.9 Data Stress Strain for Specimen 9 50 4.3.1.0 Data Stress Strain for Specimen 10 51 4.3.1.1 Data Stress Strain for Specimen 11 52
4.3.1.2 Data Stress Strain for Specimen 12 53 4.3.1.3 Data Stress Strain for Specimen 13 54 4.3.1.4 Data Stress Strain for Specimen 14 55 4.3.1.5 Data Stress Strain for Specimen 15 56 4.3.1.6 Data Stress Strain for Specimen 16 57 4.3.1.7 Data Stress Strain for Specimen 17 58 4.3.1.8 Data Stress Strain for Specimen 18 59 4.3.1.9 Data Stress Strain for Specimen 19 60 4.3.2.0 Data Stress Strain for Specimen 20 61
LIST OF SYMBOLS MPa = Unit for Tensile Strength 0 C = Celsius CNC = A lathe that is controlled by a computer running Programming driven by numerical data mm = milimetre % = Percentage Al = Aluminum T = Temperature N = Newton S = Second
LIST OF APPENDIXS NO TITLE PAGES 1 Gantt Chart PSM 1 79 2 Gantt Chart PSM 2 79 3 Poster PSM 1 80 4 Poster PSM 2 81 5 Graph Load Versus Extension 82-91
1 CHAPTER 1 INTRODUCTION 1.1 BACKGROUND In recent years, aluminium alloys have attracted attention of many researcher, engineers and designers as promising structural materials for automotive industry or aerospace applications. Aluminium alloys are alloys in which aluminium is the predominant metal. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required. There are many type of aluminium alloy series in it alloy systems which the each series has their own mechanical and physical properties depends on the composition in that alloys. (P.J Gregson and S.J Harris, 2002). Aluminium alloys can be divided into two categories: non-heat treatable and heat treatable. Extensive studies have been done on the 6xxx aluminium alloys because of their benefits compared to the other type of aluminium. It has good mechanical properties and exhibits good weldability. The 6061 aluminium alloys has been used in the automotive industry for the fabrication of several types of automobile parts such as wheel spacers, panels and even in the vehicle structure. Several of aluminium alloy mechanical properties can be change by doing a specific heat treatment. Generally aluminium alloys can be heat treated to increase their mechanical properties especially their strength, hardness and also improves their fatigue resistance.
2 1.2 PROBLEM STATEMENT A lot of researches have been done by the researcher all around the world on this aluminium alloy especially for industrial use. They have studied about the strength, formability, weldability and many more. The effect of variation aging time on machinability of 6061 aluminium alloy which has been heat treated to specific temperature has been investigate in this project. The purpose is to see whether the 6061 aluminium alloy mechanical properties is being affected or not by the variation aging time at specific temperature. Then the result is being compared to the result from the previous experiment that has been done by other researchers. Aluminum is one of the most widely used metals and also one of the most frequently found compounds in the earth s crust. Disadvantages of Aluminum is not particularly strong the strongest varieties are around 517 MPa tensile strength, is not very hard and it s easy to scratch. As a result, this project is to try to prove that the hardness after the Heat Treatment larger than before the Heat Treatment. In addition, it also perform microstructure which it described on it behaviours. These could be divided to Mechanical Properties as Young s Modulus, ultimate Tensile Strength, Tensile Strength and Yield Strength. Besides, the strength of material had a difference before and after the Heat Treatment. Nowadays, better and more consistent alloys and composite materials are all contributing to new structural designs [1]. Among the light metals, although aluminium itself is soft and low in strength it can be made stronger by giving proper combination of suitable alloy [2]. Figure 1.2: Cup and Cone Aluminium Fracture (Source: H.W. Hayden, W.G Moffatt and J. Wulf, (1945) )
3 1.3 OBJECTIVES The objectives of the project that need to be achieved are: 1. To study the effect of aging treatment on hardness of aluminium alloy after Heat Treatment in comparison cooling in air and cooling in furnace. 2. To study the effect of aging treatment to mechanical properties of aluminium alloy after Heat Treatment Process in comparison cooling in furnace and cooling in air. 1.4 SCOPES The focus area will be done based on the following aspect: 1. 6061 aluminium alloy sample preparation. 2. Aging Treatment temperature at 150 C, 200 C and 250 C. 3. Artificial aging of sample at 1 hour, 3 hours and 5 hours. 4. Specimen preparation by using the CNC Lathe machine. 5. ` Microstructure observation by using optical microscope. 6. Tensile Test by using INSTRON Equipment 7. Hardness test by using hardness test machine. 1.5 OVERVIEW OF THE REPORT This project has been sort into six chapters. The introduction of the project has been show in chapter 1. In chapter 2, the literature review has been explained. Methodology is being told in chapter 3 while in chapter 4 are result, chapter 5 are discussion and lastly chapter 6 about conclusion.
4 CHAPTER 2 LITERATURE REVIEW Literature review is a body of text that aims to review the critical points of current knowledge and or methodological approaches on a particular topic. In this chapter, the literature that will give information about this project and what happen during this experiment is being discussed. This project is intended to provide a lot of information about extensive background of Heat Treatment process with detail explanations as a reference for this project. The chapter begins with general overview of Heat Treatment and it types, details about Aluminum and few types of Testing. 2.1 ALUMINIUM Aluminium, symbol Al, the most abundant metallic element in the Earth's crust. The atomic number of aluminium is 13; the element is in group 3 of the periodic table. Pure aluminium has a face centred cubic crystal structure. Aluminium is a very light metal with a specific weight of 2.7 kg dm 3, about a third that of steel. For example, the use of aluminium in vehicles reduces dead-weight and energy consumption while increasing load capacity. Its strength can be adapted to the application required by modifying the composition of its alloys and by various thermal and mechanical treatments. Aluminium naturally generates a protective oxide coating and is highly corrosion resistant. Different types of surface treatment such as anodising, painting or lacquering can
5 further improve this property. It is particularly useful for applications where protection and conservation are required. Aluminium is an excellent heat and electricity conductor and in relation to its weight is almost twice as good a conductor as copper. This has made aluminium the most commonly used material in major power transmission lines. Aluminium is a good reflector of visible light as well as heat, and that together with its low weight makes it an ideal material for reflectors in, for example, light fittings or rescue blankets. Aluminium is ductile and has a low melting point and density. In a molten condition it can be processed in a number of ways. Its ductility allows products of aluminium to be basically formed close to the end of the products design. Aluminium foil, even when it is rolled to only 0.007 mm thickness, is still completely impermeable and let s neither light aroma nor taste substances out. Moreover, the metal itself is non-toxic and releases no aroma or taste substances which make it ideal for packaging sensitive products such as food or pharmaceuticals. Aluminium is 100% recyclable with no downgrading of its qualities. The re-melting of aluminium requires little energy: only about 5% of the energy required to produce the primary metal initially is needed in the recycling process Figure 2.1: Element of Aluminium (Source: Greg Robson)
6 2.2 ALUMINIUM ALLOY Aluminium alloys are alloys in which aluminium is the predominant metal. Typical alloying elements are copper, zinc, manganese, silicon, and magnesium. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al-Si, where the high levels of silicon (4-13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required. Figure 2.2: Production