Parametric Effects on Mechanical Properties of Aluminium Silicon Alloy using Powder Metallurgy Technique

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1 7 Parametric Effects on Mechanical Properties of Aluminium Silicon Alloy using Powder Metallurgy Technique 1 Rajender, 2 Kuldeep Malik, 3 Jagdeep Sangwan 1,2,3 Department of Mechanical Engineering Satpriya Group of Institutions, Rohtak(Haryana) Abstract Powder metallurgy offers an alternate technology, enabling us in producing alloys having improved fatigue, corrosion, and stress-corrosion resistance, as well as improved toughness and strength at room or elevated temperatures. In the present research work, experiments were performed using different parameters and different compositions of powder. Three compositions of powder were used as given under-: (1) Silicon 6% by weight, iron 1% by weight and rest amount of aluminum (Al-6Si-1Fe) (2) Silicon 8% by weight, iron 1% by weight and rest amount of aluminum (Al-8Si-1Fe) (3) Silicon 10% by weight, iron 1% by weight and rest amount of aluminum (Al-10Si-1Fe) Using powder sample (Al-6Si-1Fe), specimen pieces were made at different compacting pressure (1.5 ton, 2 ton, 2.5 ton, 3 ton, 3.5 ton). It was seen that the relative density of aluminum alloy increases with the increase in compacting pressure (near about 1 at 3.5 ton). Using powder sample (Al-6Si-1Fe), specimen pieces were made at same compacting pressure but sintering temperature is kept different (400 C, 420 C, 445 C) for each piece. It was seen that the relative density of aluminum alloy also increases with increase of sintering temperature. Using powder samples (Al-6Si-1Fe), (Al-8Si-1Fe) and (Al- 10Si-1Fe), mechanical tests (compression test, tensile test and hardness test) were performed with the help of different parameters. And it was found that an aluminum alloy having silicon 5 to 10 % by weight, iron 1% by weight and rest amount of aluminum, have excellent mechanical properties when sintered at a temperature of 400 0c to 445 0C. Keywords: Metallurgy, solid metal, PM, Power. 1 Introduction The process of blending off the fine powdered materials, pressing them into a desired shape or form (compacting), and then heating the compressed material in a controlled atmosphere to bond the material (sintering). The powder metallurgy process generally consists of four basic steps :powder manufacture, powder blending, compacting, and sintering. Compacting is generally performed at room temperature, and the elevatedtemperature process of sintering is usually conducted at atmospheric pressure. Optional secondary processing often follows to obtain special properties or increased precision. Two main techniques used to form and consolidate the power are (a) and (b) Metal Injection molding. Recent developments have made it possible to use manufacturing techniques which use the metal powder for the products. Because with this techniques, the powder is melted and not Sintered, better mechanical strength can be accomplished.[11]. 1.1 Powder metallurgy process After the metallic powders have been produced, the conventional powder metallurgy process consists of three main steps that are discussed as below- (i) Blending & mixing of powders (ii) Compaction (iii) Blending : Blending is a process of mixing up of powders of the same chemical composition but different sizes. Mixing : A process of combining powders of different chemical composition. Blending and Mixing is done by mechanical means: (i) Rotating drum (ii) Rotating double cone

2 8 (iii) Screw mixer (iv) Blade mixer Except those powders some other ingredients are also added. Some of them are given as under- (a) Lubricants: to reduce the particles Die friction (b) Binders: To achieve enough strength before. (c) Deflocculates: To improve the flow characteristics during feeding[11]. 2 OBJECTIVES OF THE STUDY From the above literature review it is calculated that aluminum is an important material. So in this research work properties of aluminum alloy with various parameters are studied and the following objectives are made to fulfill the research work-; (1) To enhance the Mechanical properties of Aluminium alloy. (2.) To study the advantages and disadvantages of aluminum alloy produced by powder metallurgy techniques. (3) To study the effect of iron and silicon percentage on aluminum alloy (4) To produce light weight aluminum alloy (5) To compare the powder metallurgy process with casting. 4 EXPERIMENTAL SETUP Research work on powder metallurgy consists of following phases- Phase 1 Preparation of powder samples Phase 2 Preparation of die Phase 3 Manufacturing of specimen pieces by powder metallurgy techniques Phase 4 Conduction of various mechanical tests and to conclude the result 5 RESULTS AND DISCUSSION 5.1 Densification Densification of Aluminum alloys powder preform is governed by several factors, which interact with each other in a complex manner. Some of the important factors considered here are as follows: Powder Particle Size Powder particle size has a remarkable effect on the relative density of aluminum alloy Which affects the deformation characteristics and fracture mechanisms of the metal powder preforms. The decrease in grain size of powder, however, results in more densification and improvement informability of the powder performs. Poor flow rate for finer particles are also observed. 3 METHODOLOGY To make the compacts of different compositions following steps are used as under-: i. Preparation of metallic powder samples ii. Mixing and blending of powder samples of different compositions iii. Preparation of die for compacting iv. Compaction of powder under high pressure v. of green compacts under high temperature (below melting point ). vi Testing of various properties of compacts Compacting Pressure Table 1 shows the relative density variation with the increase in compacting pressure. It was seen that the relative density of the Aluminum alloys powder preforms (Al-6Si-1Fe) increases gradually with increase in compacting pressure. The formability of Aluminum alloys powder preforms improves at higher compacting pressure. These compacts are sintered at 445 C temperatures. From figure we can conclude that compacting pressure range for aluminum components is 3 tones to 4 ton per inch square for better quality and for obtaining relative density near to 1. i.e. density of aluminum powder components approaches to the density of solid aluminum. Table 1 Relation between Compacting load and relative density

3 9 Sr. No. Load (ton) Relative Density Figure 5.1 Load v / s relative density plot for Al-6Si-1F Figure 5.2 Load v/s relative density plot for Al-6Si-1Fe 5.2 Effect of temperature on the microstructure of Aluminium Effect of temperature on microstructure of aluminum is shown in the figure Temperature The purpose of sintering is to improve the strength of green compacts. Table 2 shows the variation of relative density with the sintering temperature for performs (Al-6Si-1Fe)compacted at 3.5 ton. It is observed that the relative density of the Aluminum alloys powder perform increases with the increase in sintering temperature and compacting pressure. Table 2 shows relative density increases with the increase in sintering temperature. It is experimentally found that the pieces held at greater sintering temperature have high density as compared to the pieces that are hold at relatively low sintering temperature. This difference in the density occurs due to the bonding formation between the powder particles. At relatively high sintering temperature, crystallization takes place and bonding starts between the particles as a result void reduced in the metal perform hence density increases. Table 2 Relation between sintering temperature and relative density Sr. No. temp. Relative Density Aluminium ( temperature 400 C), Aluminum (sintering temperature 420 C) Fig. 5.3 Effect of various Temperature on Al Microstructure The above figure of Microstructure shows the effects of temperature on the bonding of metal powder (Al-6Si-1Fe). These micrograph shows that the grain size was enlarged approximately two times (from about 100 micron at 400 C to about 175 micron at 445 C after 180 minutes ). Grain size increases with the increase in temperature. At low temperature bonding between the particles does not take place. From temperature 400 C to 445 C, when there is an increase in the sintering temperature, crystallization stage reached where bonding between particles takes place which result

4 10 in the uniform micrograph as shown in above figure for sintering temperature 445 C. 5.3 Powder Metallurgy v/s Casting A comparative study has been done on Mechanical properties of Aluminum alloy made from powder metallurgy and casting. It is found that there is an improvement in the properties, in the case of powder metallurgy process. Properties which has been tested, their comparative study are given as below Particle Size Powder particle size has a remarkable effect on the behavior of aluminum alloy metal. It affects deformation characteristics and fracture mechanisms of the metal powder performs Aluminum alloy powder is compacted at the load of 3.5 to 4.5 ton and sintered at 400 C, 420 Cand 445 C temperatures. It is found that the grain size of compacted piece is comparatively smaller than casting.decrease in grain size of powder results in more densification and improvement in formability of the powder performs. Table 3 Compressive strength Sr. No. Samples Deformation point 1 Powder Metallurgy 1.6 ton 2 Casting 1.3 ton 5.4 Hardness testing It is the ability of a metal /Material to resist being permanently deformed (bent, broken, or have its shape changed),when a load is applied.the greater the hardness of a material,greater will be the resistance to deform. Vickers Hardness testing of pieces was done for composition iron 1% by weight,silicon 6 % to 10 % by weight and the rest amount of Aluminium percentage. Taguchi method Taguchi method is a statistical method to improve the quality of manufactured products. A technique for designing and performing experiments to investigate process where the output depends upon many factors, to develop the best component using all possible combinations of values of those variables. By choosing certain combinations of variables in a systematic way, it is possible to separate their individual effects. Table 4 Process variable for Al -6Si-1Fe by Taguchi Method. Sr. No. Silicon Composition (%) time (Hr) temp. (deg.) Hardness (VHN) Compressive Strength Compressive strength is defined as capacity of a material to bear load without failure. Compressive strength is found improved in case of powder metallurgy. On the basis of testing report the deformation point for the material (Al- 6Si-1Fe) is 1.6 ton in powder metallurgy process. The casted Aluminum alloy material deforms at near about 1.3 ton. So it is found that the load bearing capacity of Aluminum alloy in powder process is much better than casting process Ultimate tensile strength Tensile strength is opposite of compressive strength. It is the maximum value of stress that a material can bear without failure, when stretched or pulled. Tensile strength of aluminum alloy (Al-6Si-1Fe) made by powder metallurgy is better than aluminum alloy made by casting.[7] Fig.5.4 temperature v/s Hardness (VHN) plot for Al-6Si-1Fe.

5 11 Table 5 Process variable foral-8si-1fe by Taguchi Method Sr. No Composition of Silicon (%) time (Hr) Temperature Hardness (VHN) Fig. 5.5 temperature v/s Hardness (VHN) plot for Al-8 Si-1Fe. 6 CONCLUSION AND FUTURE SCOPE 6.1 Conclusion From the present studies on powder metallurgy phenomenon, following conclusions have been drawn: 1.Relative density of aluminum alloy increases with the increase in compacting pressure (i.e. at 3.5 ton, it is near about 1). 2. Grain size increases with increase of sintering temperature and a better bonding takes place between particles at sintering temperature 400 C to 445 C which result in the uniform micrograph. 3. Tensile and compressive strength of aluminum alloy made by powder metallurgy process is much better than that of casting processes. 4. Aluminum alloy having composition of silicon 6 to 10 % by weight, iron 1 % by weight and remaining amount of aluminum, have excellent mechanical properties when sintered at temperature 400 C to 445 C temperatures. 6.2 Future scope Table 6 Process variable for Al-10Si-1Fe by Taguchi Method Sr No Composition of Silicon (%) Time (Hr) Temp. Hardness (VHN) Powder metallurgy is defined as the art and science of manufacturing useful products from metal powders. Powder metallurgy is a cost effective technique to produce products of high quality at lower cost by eliminating scraps and excess machining. Various alloying elements like Cu, Ti, Ni, Zn, Ta, Mg etc can be added to improve properties in different ratio. Atomized aluminum powder has better scope for future with the growth of aeronautics. The main aim of Powder Metallurgy Technique is to avoid the wastages of material by utilizing the thrown out material (such as scrapes or Chips) and to attain the product of our requirement (i.e. shape, design, load requirements & fulfilling other parameters). So the powder metallurgy has great future in the manufacturing of light and improved quality products. References 1. Arvind Sankhla (2015) On studies of Powder Metallurgy as an Effective Method for Processing Metal Matrix Composites Indian Journal of Applied Research Volume-5, Issue-1, ISSN X. 2. D. VOJTECH (2010) Challenges for Research and Development of New Aluminum Alloys METABK 49(3), ISSN Fig. 5.6 temperature v/s Hardness (VHN) plot for Al-10Si-1Fe 3. R. S. Rana, Rajesh Purohit and S. Das (2012) Reviews on the Influence of Alloying Elements on the Microstructure and Mechanical Properties of Aluminum Alloys and Aluminum Alloy Composites International

6 12 Journal of Scientific and Research Publications, Volume 2, Issue 6, ISSN 2250: P. Kumar, S. Ranjithkumar, C. Shanmugan, (2015) Experimental Investigation of Aluminum Silicon Carbide Composites by Powder Metallurgy Technique IJIRT Volume 1, Issue 12, ISSN: Bhaskar Raju S. A., A. R. K. Swamy and A. Ramesh (2014) Mechanical and Tribological Behavior of Aluminum Metal Matrix Composites using Powder Metallurgy Technology-A review International Journal of Mechanical Engineering & Robotic Research, Vol. 3, No. 4, ISSN M. M. Dave and K. D. Kothari (2013) Composite Material-Aluminum Silicon Alloy: A Review International Journal of Research, Volume-2, Isuue-3, ISSN Vipin Kumar, Husain Mehdi and Arpit Kumar (2015) Effect of Silicon Content on Mechanical Properties of Aluminum Alloy IRJET, Volume -2, Issue-4, July 2015, ISSN C. Saravanan, K. Subramanian, V. Ananda Krishnan and R. Shankara Narayanan (2015), Effect of Particulate Reinforced Aluminum Metal Matrix Composite-A Review Mechanics and Mechanical Engineering, Vol. 19, Page Ahmed Sahib Mahdi, Mohd Sukri Mustapa, Mohd Amri lajis and Mohd warikh abd Rashid (2016) Effect of sintering Temperature on compression strength and Microhardness of recycling Aluminum alloy AA6061 through Ball Mill Process ARPN Journal of Engineering and Applied Sciences, Vol 11, ISSN P. B. Pawar and Abhay A. Utpat (2014) Development of Aluminum based Carbide Particulate Metal Matrix Composite for Spur Gear International Conference on Materials and Characterization