Me2151
ME2151-2 METALLOGRAPHY
2012/2013
Department of Mechanical Engineering National University of Singapore
CONTENTS
TABLE OF CONTENTS LIST OF ILLUSTRATIONS INTRODUCTION METALLOGRAPHIC PREPARATION OF SPECIMENS THEORY OF WELD STRUCTURE SCOPE PROCEDURE REFERENCES LIST OF ILLUSTRATIONS Figure 1 Figure 2 Fe-Fe3C Phase Diagram Schematic of Weld Structures
(i) (i) 1 1 2 5 5 6
3 4
INTRODUCTION
Metallography can be defined as the visual study of the constitution and structure of materials. Metallographic examinations can be broadly classified into two types namely, macroscopic examinations and microscopic examinations. Macroscopic examinations refer to the observations carried out at a magnification of X10 of less. Microscopic examinations, on the other hand, refer to the examination of the structure at a magnification greater than X10. Microscopic examinations, depending on the nature of information to be extracted, can be accomplished using an Optical Microscope (up to X2000) or Scanning Electron Microscope (up to X 50000) or a Transmission Electron Microscope (up to X500000). For most of the routine purposes in optical microscope is used to obtain first hand information on the geometric arrangement of the grains and phases in a material. In order to retain the information visualized using the microscope, microstructural details are often recorded on a 35 mm film or a Polaroid film. The photograph thus obtained, revealing the microstructural details, taken at a magnification of greater than X10 is known as a photomicrograph. Maintaining a record of the microstructural studies in the form of photomicrographs is a common practice employed by research scholars and leading laboratories all over the world. The study of microstructaral details is important due to its correlation with the ensuing mechanical properties of the material. As an example, if material A exhibits a more homogeneous and refined microstructure than material B , it may very well be
2012/2013
Department of Mechanical Engineering National University of Singapore
CONTENTS
TABLE OF CONTENTS LIST OF ILLUSTRATIONS INTRODUCTION METALLOGRAPHIC PREPARATION OF SPECIMENS THEORY OF WELD STRUCTURE SCOPE PROCEDURE REFERENCES LIST OF ILLUSTRATIONS Figure 1 Figure 2 Fe-Fe3C Phase Diagram Schematic of Weld Structures
(i) (i) 1 1 2 5 5 6
3 4
INTRODUCTION
Metallography can be defined as the visual study of the constitution and structure of materials. Metallographic examinations can be broadly classified into two types namely, macroscopic examinations and microscopic examinations. Macroscopic examinations refer to the observations carried out at a magnification of X10 of less. Microscopic examinations, on the other hand, refer to the examination of the structure at a magnification greater than X10. Microscopic examinations, depending on the nature of information to be extracted, can be accomplished using an Optical Microscope (up to X2000) or Scanning Electron Microscope (up to X 50000) or a Transmission Electron Microscope (up to X500000). For most of the routine purposes in optical microscope is used to obtain first hand information on the geometric arrangement of the grains and phases in a material. In order to retain the information visualized using the microscope, microstructural details are often recorded on a 35 mm film or a Polaroid film. The photograph thus obtained, revealing the microstructural details, taken at a magnification of greater than X10 is known as a photomicrograph. Maintaining a record of the microstructural studies in the form of photomicrographs is a common practice employed by research scholars and leading laboratories all over the world. The study of microstructaral details is important due to its correlation with the ensuing mechanical properties of the material. As an example, if material A exhibits a more homogeneous and refined microstructure than material B , it may very well be
References: 1. 2. 3. 4. 5. 6. 7. W.D. Callister, Jr.,in "Material Science and Engineering, An Introduction," (John Wiley And Sons (SEA) Pte Ltd, Singapore, 1994). R.E. Reed - Hill and R. Abbaschian, in "Physical Metallurgy Principles,"(PWS- Kent Publishing Co., Boston, USA, 1992). Metals Handbook, ASM Desk Edition, Eds: H.E. Boyer and T.L. Gall, ASM, Metals Park, OH, USA, Vol. 2, 1985. Metals Handbook: Metallography and Microstructure, Vol. 9, 9th Edition, ASM, Metals Park, OH, USA, 1985. M.N.A. Hawlader, Metallography Laboratory Manual, 1984. D.S. Clark and W.R. Varne, in "Physical Metallurgy for Engineers", (Van Nostrand, 1962). G.L. Kehl, in "The Principles of Metallographic Laboratory Practice", (McGraw-Hill, 1949).