Physical Metallurgy Lab Report PDF

PHYSICAL METALLURGY LAB REPORT REPORT ON: - MICROSTRUCTURE OF brasses (Cu-30 Zn and Cu-40 Zn) and bronzes (tin bronze) INTRODUCTION: - The study of microstructure of materials is known as metallography. It helps us to understand the different types of arrang...

PHYSICAL METALLURGY LAB REPORT REPORT ON: - MICROSTRUCTURE OF brasses (Cu-30 Zn and Cu-40 Zn) and bronzes (tin bronze) INTRODUCTION: - The study of microstructure of materials is known as metallography. It helps us to understand the different types of arrangements, patterns and structure of materials at micron level. It also helps in understand about the different property of materials. In this report, we are going to see the metallography of brasses (Cu-30 Zn and Cu-40 Zn) wand bronzes (tin bronze). In this report, we are going to prepare a sample of brasses (Cu-40Zn) for optical microscopy to study its microstructure. METHODS:-  Paper Polishing: - There are six different papers numbered 1-6 with different grit size. We start grinding the sample perpendicular to the previous orientation. We move from coarser to finer paper, subsequently changing the orientation of the sample orthogonally with each transition. Thus, with each transition damage from previous transition is removed.  Cloth Polishing:- The sample is polished using a rotating disk covered with a fine abrasive cloth. It’s important to apply gentle pressure to avoid damaging the sample. Once polished, the sample should have a mirror-like finish.  Chemical Etching:- The etching process selectively reacts with the higher energy regions of the sample, creating contrast between different areas. the etchant. After applying it to the sample, we immediately rinse it with alcohol and dry it. It's crucial not to over-etch, as this can obscure important features. If over-etching occurs, the sample needs to be re-ground and the process restarted. The etchant used in this is acidified ferric chloride this is an harmful solution and can cause cancer precaution should be taken before using.  MICROSCOPY: - The etched sample is now taken for observation under optical microscope. To set the sample on a microscopic slide, a levelling press is used. A piece of paper is kept on the surface of the sample to prevent scratches from levelling. Lastly, the sample is put under the optical microscope and the microstructure can be observed. RESULT AND DISCUSSION:- MICROSTRUCTURE OF brasses (Cu-30 Zn) 2023MMB004 MICROSTRUCTURE OF brasses (Cu-40 Zn)  Bronzes (tin bronze) 2023MMB028 Cu-30Zn: This alloy consists of around 30% zinc and 70% copper, commonly referred to as cartridge brass. Cu-40Zn: Contains approximately 40% zinc and 60% copper, and is often known as Muntz metal. Mechanical Properties:- Cu-30Zn :This alloy is recognized for its excellent formability, high ductility, and moderate strength. It's easy to work with and is particularly suitable for applications where good cold working properties are required. Cu-40Zn;While it offers higher mechanical strength than Cu-30Zn, it is less ductile. This makes Cu-40Zn better suited for uses where increased mechanical strength is essential, although it is more challenging to cold work. Corrosion Resistance: Cu-30Zn: This alloy demonstrates better resistance to corrosion, particularly in environments with freshwater, compared to Cu-40Zn. Cu-40Zn: The higher zinc content makes it more prone to dezincification (where zinc is leached out in corrosive environments). However, it does provide higher hardness and better wear resistance. Applications: Cu-30Zn: Commonly used in items such as cartridge cases, radiator cores, and plumbing accessories. Cu-40Zn: Typically found in marine fittings, condenser tubes, and large structural applications requiring additional strength. Tin Bronze (Copper-Tin Alloys) Composition:- Tin bronze alloys generally consist of 88-92% copper and 8-12% tin. Phosphorus may sometimes be added in small amounts to enhance strength and hardness. Mechanical Properties:- Tin bronze is known for its superior strength and hardness compared to brass, especially under high-stress conditions, which helps prevent deformation. Applications: Tin bronze is widely used in applications such as bearings, gears, marine hardware, and pump components due to its durability, wear resistance, and strong corrosion resistance. CONCLUSION: - During the analysis, some black spots, known as etching pits, were visible, which typically result from imperfections in the etching process. Scratches were also observed in the microstructure, likely due to errors during grinding and polishing. Additionally, over-etching can obscure the visibility of the grains and their boundaries, making the microstructure less clear REFERENCES: - https://learnmech.com/what-is-ferrite-cementite-pearlite-martensite-austenite/ https://www.bitswgl.ac.in/lab-manuals-mech/8.MMS_lab.PDF