Published on September 26, 2015
1. GUIDED BY PRESENTED BY AJIMSHA J M NIHAS NASSIR ASST. PROFESSOR S7 ME MESITAM M 12U036 1
2. CONTENT INTRODUCTION CHEMICAL COMPOSION SAMPLE PREPARATION SEM PARTS AND WORKING OF SEM AFM PARTS AND WORKING OF AFM COMPARISON STUDY ADVANTAGE OF LM-25 CONCLUSION REFERENCES 2
3. INTRODUCTION •LM 25 is an alloy of Aluminum combined mainly with 6- 7.5 % silicon , 0.2% copper and other materials . •It is corrosion resistant and strong •Excellent weldability •Application ranges from marine, electrical, automobile , nuclear and Aerospace industries . •This seminar deals with properties of the material and microstructure of material using SEM & AFM. 3
4. CHEMICAL COMPOSITION 4
5. Sample preparation 600g of LM -25 were taken and melted in electrical resistance furnace N2 is used as a degasser Graphite rod are used for stirring Pour into the mould and cast is obtained This is used as the sample 5
6. Scanning Electron Microscopy 6
7. SCANNING ELECTRON MICROSCOPE (SEM) A scanning electron microscope (SEM) is a type of electron microscope It images a sample by scanning it with a high- energy beam of electrons in a raster scan pattern. The electrons interact with the atoms of the sample It gives the information about the structures of grain, composition, and other properties 7
8. Components of SEM Electron gun Condenser Lens Aperture Scanning system Specimen Chamber 8
12. AFM Atomic Force Microscopy 12
13. Parts of AFM Laser – deflected off cantilever Mirror –reflects laser beam to photodetector Photodetector –dual element photodiode that measures differences in light intensity and converts to voltage Amplifier Register Sample Probe –tip that scans sample made of Si Cantilever –moves as scanned over sample and deflects laser beam 13
15. Contact Mode Non-Contact Mode Tapping (Intermittent contact) Mode 3 MODES OF AFM 15
16. Contact mode Measures repulsion between tip and sample. Force of tip against sample remains constant. Feedback regulation keeps cantilever deflection constant Problems: excessive tracking forces applied by probe to sample 16
17. Non contact mode Measures attractive forces between tip and sample Tip doesn’t touch sample Van der Waals forces between tip and sample is decteced and gives the AFM image 17
18. Tapping mode Tip vertically oscillates between the sample surface at a frequency of 50,000 to 500,000 cycles/sec. Oscillation amplitude reduced as probe contacts surface due to loss of energy caused by tip contacting surface. And gives the AFM image of the test specimen. 18
19. property LM-25 Aluminium Steel Density 2670 kg/m3 2730kg/m3 7750kg/m3 Melting Point 615°C 660.3°C 1370°C Elastic Modulus 71 GPa 70.0GPa 190.3GPa Tensile strength 280 mpa 714.0 mpa 500 mpa Percent Elongation 5% 20% 17% Hardness 120 BHN 100BHN 95 BHN 19 COMPARISON STUDY
20. Advantages of LM-25 good corrosion resistance • Excellent cast ability • It is corrosion resistant and strong • Excellent weldability • Application ranges from marine, electrical, automobile , nuclear and Aerospace industries 20
21. product made from LM-25 21
22. CONCLUSION The micro structural studies shows that LM-25 posses good corrosion resistance and mechanical properties Posses excellent weldability It found more application in the field of marine, electrical, automobile , nuclear and Aerospace industries 22
23. References  Association of North America 1998, pp1-31  T.V.S. Reddy, D.K. Dived, N.K. Jain, Adhesive wear of stir cast hypereutecticAl–Si–Mg alloy under reciprocating slid in conditions, Wear 266 (2009) 1–5.  J. Clarke, A. D. Sarkar, Wear characteristics of as-cast binary aluminiumsilicon alloys, wear, 54 (1979) 7 – 16.  Toni Bogdan off and Jimmy Dahlstrom,The influence of copper on an Al-Si-Mg alloy (A356) - microstructure and mechanical properties, school of engineering, Jonkoping University, june-2009, pp 10.  K.B. Shah, Sandeep Kumar and D.K.Dwived, Aging temperature and abrasive wear behavior of cast Al– (4%, 12%, 20%)Si–0.3% Mg alloys,Dec 2004. 23
Starting from the study of the addition of pure Nb ... Fig. 3 shows representative macro- and microstructural images of the LM 25 alloy without the ...
... (LM 25/356) alloy. Modification ... Microstructural observation and thermal analysis of Al-21 wt % Si alloys with ... Studies of Mechanical Properties ...
... LM-25 or LM-24 must use cast iron ... So in the present work an effort has been made to study the effect of minor ... Microstructural Studies
Studies on the effect of minor addition of ... (6.0 per cent Si), 356/LM-25 (7 per cent Si) or ... 3.1 Microstructural studies
... respectively, while microstructural analyses by scanning electron microscopy ... In this study, ... (LM 25/356) alloy. M. Ravi, ...
like structure as in the unmodiﬁed alloys. Microstructural observation showed that a minimum Bi/Sr ratio of 1 ... Research studies have reported
LM 25 cast alloy has no additional ... the work performed aiming to study laser welding of dissimilar alloys of AA6xxx series ... and microstructural ...
LM-21, LM-25 or LM24 must use cast iron cylinder liners - ... made to study the effect of minor addition of 0.02wt%-0.06wt%P on the microstructure, ...
... The main purpose of the research paper is to study the effect of refinement ... 356/LM-25 (7 per cent Si) or 380 ... 3.1 Microstructural studies. ...