ADVANCED SURFACE

ENGINEERING ENMT801016

Outline 2

About the class

Class introduction

Course content

Grading

General introduction to Advanced Surface

Engineering

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Code: ENMT801016

Subject: Advanced Surface Engineering

SKS: 3

Class: Senior Undergraduate/Graduate

Term: Second Term 2012/2013

Class meet: Wed at 6:00 8:30 pm in K.209

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The class is designed to give the students fundamental concept in improving the performance, extending the life, and enhancing the appearance of materials used for engineering components

The class will review the latest technological advancements and issues in surface engineering and its practical application for both metallic and non metallic materials.

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After taking this course the students are expected to be able to:

Describe the phenomena of changes in materials properties

associated with surface treatment processes

Selecting and designing a variety of surface treatment process

according to the selected materials and their application in

industry

Obtain a right microstructure and desired mechanical

properties according to the selected surface treatment process

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For the assignment, please note that a submission

date, time and venue will be specified at the time

of setting of each assignment.

Assignment that does not adhere to these submission

requirements will receive an automatic zero grade.

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All exam times and assignment deadlines are fixed

and the only excuses accepted for nonattendance

at an exam or non-submission of an assignment are

a serious certified illness or a family bereavement.

In such cases, a make-up exam (or make-up

assignment in the case of an assignment) of equal

or greater difficulty must be taken.

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Examinations and individual assignments are to be

the sole work of the student concerned group

efforts are not acceptable!

Students are also cautioned not to engage in any

plagiarism.

Anything that is not the students own work should

have a reference, following standard scientific

conventions.

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In such rare cases as it is necessary to include

verbatim text from an article or book, this should be

clearly placed in quotation marks.

The instructor will follow standard university

disciplinary procedures if students engage in any

form of cheating and/or plagiarism in

examinations/assignments.

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The lecture notes/handouts in this class are edited from different sources for the solely of teaching and learning purposes.

It may contain copyrighted materials from their respective owners; therefore, apart form teaching and learning purposes, this lecture note may not be reproduced, stored, or transmitted in any form or by any means.

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Students are expected to make their own notes and

only relatively few handouts will be provided so

please stop me if you cant read my writing or if I

am going too fast.

Lecture notes/handouts are provided via the web

(www.nofrijon.org) as Adobe Acrobat (PDF) files.

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To obtain handouts, please navigate my website and then click on the subjects.

You need a password to open the file, see me if you do not have one!

Questions and comments in class are strongly encouraged! The instructor both welcomes and values feedback from students regarding the course.

Office hours: DTMM 2nd Fl. W 1:00 pm 6:00 pm

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Students needing special accommodation are

encouraged to see me after class or in my office within

office hours to discuss their situation confidentially.

Students needing special accommodation should bring

their memorandum from the Program Office to me as

soon as possible; this can be discussed during an

appointment with me.

14 Exam accommodation should be arranged at least

one week in advance.

If at any time during the quarter, it is felt that the

accommodation that has been put in place is

inadequate then please consult me and/or the

professional staff in the Program Office.

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This course is self contained and so a textbook is not mandatory. However, students may also wish to consult the following excellent texts:

ASM Handbook Vol. 4; Heat Treating, ASM International, Ohio, USA, 1991.

ASM Handbook Vol. 5; Surface Engineering, ASM International, Ohio, USA, 1994.

Karl-Erik Thelning, Steel and its heat treatment, Butterworths, 1984.

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The course will be graded on the following:

Mid-semester examination: 30% of final grade

Final examination: 30% of final grade

Teamwork problem based learning: 20% of final

grade

Case study: 20% of final grade

General introduction 17

Heat Treatment

Controlled heating and

cooling of metals to alter

their physical and

mechanical properties

without changing the

product shape

Sub-discipline of materials

science and engineering

dealing with the surface of

solid matters

Surface Engineering

Heat treatment 18

Heat treatment is often associated with increasing the strength of material, but it can also be used to soften a metal and thus alter certain manufacturability objectives such as improve machining, improve formability, restore ductility after a cold working operation.

Therefore, the most beneficial manufacturing processes are the ones that not only help other manufacturing process, but can also improve product performance by increasing strength or other desirable characteristics.

Surface engineering 19

A branch of materials engineering aimed at the design, manufacture, investigation and utilization of surface layers, both technological and for end use, with the properties better than those of the core, such as mainly anti-corrosion, anti-fatigue, anti-wear and decorative.

Further, surface engineering techniques are also being used in the automotive, aerospace, missile, power, electronic, biomedical , textile, petroleum, petrochemical, chemical, steel, power, cement, machine tools, construction industries.

Why? 20

To prepare as-produced metallic materials

(semi-finished products) for the next process

and/or treatments.

To lengthening the life time of the finished-

product/materials during service.

Heat treating a metal 21

By heating and cooling (or quenching) a metal we can change its properties.

http://www.fandbfarm.com/blacksmith.html

The importance 22

For many castings the heat treatment process is a decisive part to establish the required casting performance.

Steel casting Most steel castings receive their structure and mechanical properties through a proper heat treatment.

http://www.magmasoft.de/ms/pics/HeatTreatment_320x240.gif

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Cast Iron Residual stresses play a growing role for the performance of cast iron components.

Aluminum Castings Many non-ferrous high integrity components undergo a comprehensive heat treatment to establish the required strength or ductility. E.g. T6 treatment creates the required properties, but also imposes substantial residual stresses into the casting as a function of the quenching and annealing conditions.

Metal manufacture processes 24

Raw Metals (Ores extraction products)

Powder metallurgy

Welding/ joining

Cutting (machining)

Mechanical forming (Plastic deformation)

Heat treatment

Finishing/Surface Engineering Finished Products

Heat

treatment

Semi-Finished

Products

Foundry (casting)

Metal Materials Quality

Chemical composition Microstructure

Microstructure:

Metal microstructure is in microscopic resolution (1-100 m)

Consist of several constituents such as phase, crystallite grain, crystal defects, segregation, inclusion

Inclusion (High melting point)

Grain boundary

Continuous grain boundary

precipitation

Crystal unit

(Fe = 0.86 )

Precipitation/particles in matrix

Dislocation

Schematic diagram of microstructure

Twins

Crystal Defects

Crystal defects affect mechanical and

physical properties of metal materials

Edge dislocation

Dislocation center

Burger vector)

Dislocation line

Screw dislocation

Slip step

Burger vector

Twins

Remember!

Metals with the same chemical composition may not

have identical mechanical/physical properties.

Heat treatment controls metals microstructures as so

to increase their mechanical properties.

Heat treatment optimize hardness and ductility of

metals/steels.

Obsolescence, 15%

Breakage, 15%

Surface deteroriation, 70%

Surface treatment

reduces the risk!

Factors affecting metal components malfunction

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Mould material, components etc.

16%

Grinding 5%

EDM 16%

Trimming 20%

Heat treatment 3%

Etching 2%

Assembly 11%

Milling 20%

Drilling 5%

With relative low cost of heat treatment results in longer life of components

Cost of heat treatment compared with the total

cost of manufacture process

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Typical surface layers

Surface characteristic Metal Surfaces Surface asprity Micro roughness of the surface that is composed of hills and bottoms.

Bielby layer Adsorb film: water vapour, oxygen 3 x10-10 m. Greasy film: finger print, or oil drops 3 x10-9 m.

Oxide layer Rust products with their thickness as little as 10-7 m.

Deformed layer It is due to mechanical forming of metals.

Micrograph showing subsurface deformation in leaded brass after severe sliding wear against tool steel in air.

Schematic diagram showing how the severity of plastic deformation is distributed beneath a worn metal surface in the severe wear regime.

Metalic sub-surface structure 32

Surface Parameters

dx y(x)L

1 R

L

0a

dx (X)YL

1 R

L

0

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q

Reference plane

Ra 2qR

Arithmetic mean deviation :

Root mean square deviation :

Skewness :

dyypY )(

R

1Sk

4

3

q

Kurtosis :

dyypy

q

)(R

1K

4

4

Normal distribution Sk = 0

Normal distribution K = 3

Broad and flat distribution curve : K 3

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The importance 34

Surface engineering is aimed at the design,

manufacture, investigation and utilization of surface

layers, both technological and for end use, with

properties better than those of the core, such as

mainly anti-corrosion, anti-fatigue, anti-wear and

decorative.

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Other applications include properties such as optical, thermophysical, electrical, magnetic, adhesive, ablation, passivation, inhibition, biocompatibility, diffusion and others

Modification of near-surface structure, chemistry or property of a substrate in order to achieve superior performance and/or durability.

It is an enabling technology and can impact a wide range of industrial sectors.

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Combining chemistry, physics, and mechanical engineering with metallurgy and materials science, it contributes to virtually all engineering disciplines.

It can be done on a given surface by metallurgical, mechanical, physical, and chemical means, or by producing a thick layer or a thin coating.

Both metallic and non-metallic surfaces can be engineered to provide improved property or performance.

Why surface engineering? 37

Specific properties rely on surfaces; wear, friction,

corrosion, fatigue, reflectivity, emissivity, color,

thermal/electrical conductivity, bio-compatibility

By improving durability, it reduces waste of natural

resources and energy

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Surface engineered automotive parts and

components can extend warranties and reduce

emissions.

For example: A hardened engine valve will last a

minimum of five years without replacement.

Surfaces have different properties than bulk

material / need to optimize both

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Surfaces can be completely reengineered

Surfaces can be functionalized to achieve a

specific molecular configuration

Surface engineering techniques are both varied

and complex providing a change to the outermost

material interface

Benefits 40

Extend product life (durability)

Improve resistance to wear, oxidation and corrosion (performance)

Satisfy the consumer's need for better and lower cost components

Reduce maintenance (reliability and cost)

Reduce emissions and environmental waste

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Improve the appearance; visually attractivity

Improve electrical conductivity

Improve solderability

Metallize plastic component surfaces

Provide shielding for electromagnetic and radio

frequency radiation.

Scales of surface engineering 42

Five orders of magnitude in thickness; it can vary

from several mm for weld overlays to a few atomic

layers or nanometers for physical vapor deposition

(PVD) and chemical vapor deposition (CVD)

coatings or ion implantation.

Atomic-layer deposition is also possible.

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Superlattice Coatings

Duplex Coatings Multilayer Coatings

Superhard CVD-Diamond Films

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Three orders of magnitude in hardness: Example of coating hardness range from 250-300 HV for soft metal or spray coatings, 3500 HV for Titanium Nitride PVD coatings and up to 10,000 HV for diamond coatings

Almost infinite possibilities in the range of compositions and/or microstructure

Nano-composite, nano-layered, amorphous, crystalline, quasicrystalline

Significance of surface engineering 45

It is an enabling technology

It can combine various surface treatments with thin

film and coating deposition.

It can substantially improve wear and corrosion

resistance of structural components.

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It increases component lifetime and resistance to

aggressive environments.

It can produce functional coatings that modify

biocompatibility and optical and electrical

properties of critical components

Techniques in surface engineering 47

Techniques to prepare a surface for subsequent

treatment (e.g., cleaning and descaling)

Techniques to cover a surface with a material of

different composition or structure (e.g., plating,

painting, and coating)

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Techniques to modify an existing surface

topographically, chemically, or microstructurally to

enhance its properties e.g., conventional carburizing

and nitriding, and more enhanced techniques in

glazing, abrasive finishing, and ion implantation

Techniques for the testing and characterization of

the modified surfaces extrapolated to surface-

specific applications