| TARGETED LEARNING OUTCOMES
Students will understand the implications of using Vickers indentation test to measure the hardness of hard brittle materials such as engineering ceramics. In addition, students will learn the following aspects after conducting the hardness test and evaluating the results: – How the load (when varied) affects the surface hardness. – How much deviation in the surface hardness is found from the mean and why the deviation occurs? – How the initial condition of the ceramic vary the hardness value and the human error which could affect the test results whilst taking all measurements. – The importance of using correct parameters. – Writing precise/accurate technical reports and presenting technical information in form of graphical means.
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| Important Information – Please Read Before Completing Your Work
All students should submit their work by the date specified using the procedures specified in the Student Handbook. An assessment that has been handed in after this deadline will be marked initially as if it had been handed in on time, but the Board of Examiners will normally apply a lateness penalty.
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All work will be considered as individual unless collaboration is specifically requested, in which case this should be explicitly acknowledged by the student within their submitted material.
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You must ensure you retain a copy of your completed work prior to submission.
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| Programme: | BENG (Hons) MECHANICAL ENGINEERING | Module Code:egr3025m |
| Module Title: | Material Science and Engineering (BEng) | |
| Subject: | hardness measurements of Engineering ceramics | |
| Coursework Title: | Evaluation of load dependent hardness of engineering ceramics | |
COURSEWORK BRIEF:
Title: Evaluation of Load Dependent Hardness of Engineering Ceramics
Aim
To observe the change in the surface hardness during Vickers hardness test by varying the indentation load.
Objectives
- To measure the surface hardness of a selected engineering ceramics using the Vickers indentation technique by varying indentation loads ranging from 1 to 50 Kg.
- To carefully record hardness readings measured from the hardness test in Table 2.
- To analyse data and use graphs to present results.
- To evaluate and conclude the effect of changing hardness with respect to the increasing/decreasing indentation loads.
- To evaluate the change in the indentation size with respect to the change in the indentation load.
- To evaluate the error in measurement during the Vickers indentation test.
- Construct a short but accurate 6 pages long written report.
Task
Determine the hardness of selected advance ceramic in the following range 1 Kg to 50 Kg.
Instructions
- Each group consists of 6 randomly or more selected members.
- Use the given samples of the selected engineering ceramic to conduct the hardness tests. Please state in your report which type of ceramic was used.
- Each group must use different loading conditions as shown in Table 1.
- Produce a diamond foot-print at various given indentation loading.
- Take an average of 10 readings for each indentation load using the following approach shown in Table 2.
- Record (in Table 2) the average size of the diamond foot-print for each respective hardness test. The size of the foot-print will be displayed on the hardness tester.
- Each group will test 3 different indentation loads and therefore should have 30 readings in total (10 readings for each load).
- Please ensure that a gap of 5 indentation foot-prints is left between each diamond indentation. Otherwise it is possible that your hardness reading may be invalid and inaccurate.
- Work out the average hardness reading and show the standard deviation later in the report.
Table 1 Loading conditions for each groups for the respective indentations machines
| Groups | Machines(SVD 432)
30 Kg max |
Machines(SVD 452)
50 Kg max |
| Loads | Loads | |
| 1 | 3, 5, 20 | N/A |
| 2 | 1, 10, 30 | N/A |
| 3 | 1, 10, 20 | N/A |
| 4 | 3, 20, 30 | N/A |
| 5 | 1, 5, 20 | N/A |
| 6 | N/A | 2, 10 , 30 |
| 7 | N/A | 5, 20, 50 |
| 8 | N/A | 1, 5, 20 |
| 9 | N/A | 5, 10, 30 |
| 10 | N/A | 2, 10, 20 |
Table 2 Experimental approach showing hardness and indentation size.
For example Group 4 (using SVD 432 – 30 Kg)
| Loads (Kg) | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 | AVE | STDV
|
|
| HV | HV | HV | HV | HV | HV | HV | ||
| 1 | 1258 | 1245 | 1222 | 1355 | 1189 | |||
| Indentation Size (μm) | 38.438.4
38.4 |
38.638.6
38.6 |
39.438.5
38.9 |
34.639.4
37 |
3940
39.5 |
|||
| 10 | 1302 | 1332 | 1335 | 1527 | 1217 | |||
| Indentation Size (μm) | 119.8118.9
119.3
|
112.1123.9
118 |
117117
117 |
104.2116.2
110.2 |
119.7127.2
123.4 |
|||
| 30 | 1370 | 1233 | 1157 | 1191 | 1180 | |||
| Indentation Size (μm) | 199.3203.7
201.5 |
212.1212.8
212.4 |
213.7224.8
219.2 |
213.3219
216.1 |
218216.2
217.1 |
|||
Deliverables for the Lab Report
Evaluate the effect of indentation load upon the hardness of the selected ceramic with respect to following aspects:
- Comment on how and why the indentation load (when varied) affects the surface hardness?
- Comment on the variation of the surface hardness values found. In other words, how much deviation in the surface hardness is found from the mean and why?
- Does the initial condition of the ceramic vary the hardness value? If so then why?
- Comment on the human error whilst taking all measurements.
- Comment on the importance of using correct parameters.
Test Material: Samples may range from Zirconia (ZrO2), Silicon carbide (SiC), Silicon Nitride (Si3N4) and to Alumina (Al2O3) ceramics for different groups. Please state clearly on your report which material you have tested.
MARKING CRITERIA:
Coursework will be marked according to the following university criteria.
90-100%: a range of marks consistent with a first where the work is exceptional in all areas;
80-89%: a range of marks consistent with a first where the work is exceptional in most areas.
70-79%: a range of marks consistent with a first. Work which shows excellent content, organisation and presentation, reasoning and originality; evidence of independent reading and thinking and a clear and authoritative grasp of theoretical positions; ability to sustain an argument, to think analytically and/or critically and to synthesise material effectively.
60-69%: a range of marks consistent with an upper second. Well-organised and lucid coverage of the main points in an answer; intelligent interpretation and confident use of evidence, examples and references; clear evidence of critical judgement in selecting, ordering and analysing content; demonstrates some ability to synthesise material and to construct responses, which reveal insight and may offer some originality.
50-59%: a range of marks consistent with lower second; shows a grasp of the main issues and uses relevant materials in a generally business-like approach, restricted evidence of additional reading; possible unevenness in structure of answers and failure to understand the more subtle points: some critical analysis and a modest degree of insight should be present.
40-49%: a range of marks which is consistent with third class; demonstrates limited understanding with no enrichment of the basic course material presented in classes; superficial lines of argument and muddled presentation; little or no attempt to relate issues to a broader framework; lower end of the range equates to a minimum or threshold pass.
35-39%: achieves many of the learning outcomes required for a mark of 40% but falls short in one or more areas.
30-34%: a fail; may achieve some learning outcomes but falls short in most areas; shows considerable lack of understanding of basic course material and little evidence of research.
0-29%: a fail; basic factual errors of considerable magnitude showing little understanding of basic course material; falls substantially short of the learning outcomes for compensation.
MARKING SCHEME:
Begin your work on the following page if you are word processing your coursework
(delete this page if hand-writing)
Report Structure and Style Marks
Abstract (10 %)
- Introduction (10 %)
- Experimentation and Methodology (10 %)
- Results (20 %)
- Discussion (35 %)
Conclusions (10 %)
References (5 %)
Appendices (optional)
- 5 line spacing. 12 Font size (Times new roman or Cambria).
- Please use references if need be. Use the University recommended format.
- Use appendix if need be. Use of diagrams for explanation of concepts is welcome.
- Use of wider literature is advised and it is recommended that you include all the aspects in the deliverables in Section 4 of the report as a minimum.
- Results and Discussion (section 3 & 4) can be either combined or presented separately.
- The main body of the report should be 6 pages max.
