paraphrase material engineering lab report

Maya Saad

Lab Time: (Monday 2:00 PM)

Lab Group # 2

MSE 227 Lab # (2)- Notched Bar Impact Testing of Materials

10/29/2012

Abstract :

The “Notched Bar Impact Testing of Materials” is an experiment that requires using of the Charpy Testing Machine. This experiment involves examining five samples of each of the 1018 steel and 2024 aluminum when placed under different conditions and temperatures for a certain amount of time. These specimens are later transferred to the charpy machine using a special tongue to place the specimens in the right position. Hence, this experiment gives knowledge about the width, impact energy and shear percentage of each of the samples.

Procedure :

1. Using a hammer and a punch, carefully label each specimen.

2. Measure and record the initial width for each of the different specimens. (Five of the 2024 aluminum and five of steel 1018).

3. Apply the impact test of each of the five 1018 steel samples, as well as the 2024 aluminum samples by placing them under different conditions and temperature. That is place the specimens in dry ice/acetone bath (at -79°C), anti-freeze/ water mix with some dry ice (-40°C), ice water (0°C), room temperature (23°C), and boiling water(100°C) for ten minutes.

4. Use the special tongs to remove the specimens and place them in the correct position, which is having a straight angle with the hammer. Record the impact energy.

5. Measure and record the lateral dimensions after impact.

6. Examine and analyze the fractures of each of the specimens and look for cleavage and shear, and approximate the fraction area of each.

Results and Discussions :

After doing the experiment “Notched Bar Impact Testing of Materials” and applying all the required conditions and tests it is shown that the initial width for both, Aluminum 2024 and steel 1018, were lower than the width measured after the reaction has taken place. The lateral dimensions for each of the steel and aluminum are presented in Tables 1.1 and 2.1 respectively.

Moreover, it is also recognized that after applying the impact test, the fracture energy for steel 1018 is higher than that of 2024 Aluminum. Also, it is shown that the shear percentages for the 2024 Aluminum is constant; while for the 1018 steel, it starts to increase as temperatures increases. The fracture energy values and the Shear percentages of the 1018 steel and 2024 aluminum are shown in Tables 1.2 and 2.2 respectively.

Additionally, the average values of steel 1018, as well as the lower and upper standard deviation values are shown in Table 1.3. While the values for the 2024 Aluminum are presented in table 2.3.

Furthermore, the variation of impact energy versus temperature for each of the 1018 steel and the 2024 aluminum are shown in graph 1.1. For the 2024 Aluminum, the variation of impact energy versus test temperature is approximately constant while the variation of impact energy versus temperature for steel 1018 starts constant and then starts to increase as temperature increases till 0°C, after that it becomes stable again. In addition, Graph 1.2 represents the changes in width versus Temperature for each of the 2024 Aluminum and 1018 Steel. As temperature increases, the change in width slightly decreases for aluminum 2024. While for 1018 steel, the change in width starts low, then when temperature reaches -40°C it starts to increase till reaching 0°C; after this temperature it starts to decrease slightly again.

Moreover, Graph 1.3 indicates the shear percentages versus test temperature for both the 2024 Aluminum and 1018 Steel. The shear percentage for aluminum remained constant under all the different temperatures that were used, while the shear percentage for steel increases as temperature increases. In addition, the average fracture energy, upper and lower standard deviation versus temperature for the 1018 steel and 2024 aluminum are displayed in graphs 1.4, and 1.5 respectively. The 1018 steel average fracture energy increases slowly as temperature increases while the fracture energy for aluminum remains approximately constant for all the temperatures used. The lower standard deviation for both steel and aluminum is almost stable. On the other hand, the upper standard deviation for steel increases while temperature increases till it reaches 0°C, then it starts decreasing between the 0°C and 20°C, till it increases again. On the other hand, the upper standard deviation for Aluminum increases as temperature increases till it reaches -40°C, these values decreases when the temperature ranges between -40°C and 20°C, then it increases again. Hence, the upper standard deviation for both steel and aluminum increases after the 20°C temperature.

Table 1.1 The Initial Width of Steel 1018 Compared to the Final Width When Placed in Different Temperatures.

Symbol	Initial Width	Condition/Temperature	Final Width
“5”	0.379 in	Dry ice/acetone bath(-79°C)	0.386 in/0.387 in
“T”	0.379 in	Antifreeze/water mix with some dry ice (-40°C)	0.389 in/0.388 in
“P”	0.379 in	Ice/pure water (0°C)	0.423 in/ 0.428 in
“&”	0.379 in	Room temperature(23°C)	0.410 in / 0.433 in
“Z”	0.378 in	Boiling water (100°C)	0.412 in/ 0.422 in

Table 1.2. Fractured Energy Values and Shear Percentages of Steel 1018:

Symbol	Condition/Temperature	Fractured Energies	Shear Percentages
“5”	Dry ice/acetone bath(-79°C)	18.2 ft.lb	16
“T”	Antifreeze/water mix with some dry ice (-40°C)	20.9 ft.lb	25
“P”	Ice/pure water (0°C)	76.9 ft.lb	53
“&”	Room temperature(23°C)	86.2 ft.lb	65
“Z”	Boiling water (100°C)	84.5 ft.lb	81

Table 1.3 Averages of 1018 Steel, as well as Lower and Upper Standard Deviation

Values.

Symbol	Condition/ Temperature	1018 Steel (Average)	Lower Standard Deviation	Upper Standard Deviation
“5”	Dry ice/acetone bath(-79°C)	9.63	4.78	22.87
“T”	Antifreeze/water mix with some dry ice (-40°C)	24.07	7.96	63.30
“P”	Ice/pure water (0°C)	53.30	12.39	153.50
“&”	Room temperature(23°C)	73.00	5.90	34.83
“Z”	Boiling water (100°C)	88.35	11.72	137.39

Table 2.1 The Initial Width of Aluminum 2024 Compared to the Final Width When Placed Under Different Conditions:

Symbol	Aluminum 2024-Initial Width	Temperature / Condition	Final Width
“D”	0.373 in	Dry ice/acetone bath(-79°C)	0.396 in
“E”	0.372 in	Antifreeze/water mix with some dry ice (-40°C)	0.389 in / 0.392 in
“W”	0.371 in	Ice/pure water (0°C)	0.389 in
“S”	0.372 in	Room temperature(23°C)	0.390 in/ 0.398 in
“K”	0.372 in	Boiling water (100°C)	0.380 in / 0.393 in

Table 2.2 Aluminum 2024 Fracture Energy Values and Shear Percentages are Presented Below:

Symbol	Temperature / Condition	Fracture Energy	Shear Percentages (%)
“D”	Dry ice/acetone bath(-79°C)	13.0 ft.lb	45
“E”	Antifreeze/water mix with some dry ice (-40°C)	15.05 ft.lb	45
“W”	Ice/pure water (0°C)	13.6 ft.lb	45
“S”	Room temperature(23°C)	13.4 ft.lb	45
“K”	Boiling water (100°C)	15.3 ft.lb	45

Table 2.3 Averages of 2024 Aluminum, as well as Lower and Upper Standard Deviation.

Symbol	Temperature / Condition	2024 Aluminum (Average)	Lower Standard Deviation	Upper Standard Deviation
“D”	Dry ice/acetone bath(-79°C)	8.85	1.77	3.14
“E”	Antifreeze/water mix with some dry ice (-40°C)	8.77	2.22	4.91
“W”	Ice/pure water (0°C)	8.82	1.86	3.48
“S”	Room temperature(23°C)	8.95	1.74	3.03
“K”	Boiling water (100°C)	9.10	2.13	4.55

Graph 1.1 Impact Energies versus Test Temperature for 2024 Aluminum and 1018 Steel.

Graph 1.2 Changes in Width versus Temperature for each of the 2024 Aluminum and

1018 Steel.

Graph 1.3 Shear Percentages versus Test Temperature for both 2024 Aluminum and

1018 Steel

Graph 1.4 The Average Fracture Energy, Upper and Lower Standard Deviation versus

Temperature for the 1018 steel

Graph 1.5 The Average Fracture Energy, Upper and Lower Standard Deviation versus Temperature for the 2024 Aluminum

References:

Callister, William D., and David G. Rethwisch. Fundamentals of Materials Science and

Engineering: An Integrated Approach. Hoboken, NJ: John Wiley & Sons, 2008.

Print.

Fracture Energy vs. Temperature

2024 Aluminum (Avg) -79 -40 0 23 100 8.8461499999999997 8.7730800000000002 8.8153799999999993 8.9538499999999992 9.1 Standard Deviation (-) -79 -40 0 23 100 1.7722899999999999 2.2161 1.8645099999999999 1.74003 2.1322899999999998 Standard Deviation (+) -79 -40 0 23 100 3.1410118440999999 4.9110992099999997 3.4763975400999998 3.0277044008999998 4.5466606440999993

Temperature (°C)

Fracture Energy (ft-lb)

Impact Energy vs. Temperature

2024 Aluminum -79 -40 0 23 100 13 15.05 13.6 13.4 15.3 1018 Steel -79 -40 0 23 100 18.2 20.9 76.900000000000006 86 84.5

Temperature (°C)

Impact Energy (ft/lb)

Changes in Width vs. Temperature

2024 Aluminum -79 -40 0 23 100 2.300000000000002E-2 1.8500000000000016E-2 1.8000000000000016E-2 1.8000000000000016E-2 1.4000000000000012E-2 1018 Steel -79 -40 0 23 100 7.5000000000000067E-3 9.5000000000000084E-3 4.6499999999999986E-2 4.2499999999999982E-2 3.8999999999999979E-2

Temperature (°C)

Δ Width (in.)

Shear Percentage vs. Temperature

2024 Aluminum -79 -40 0 23 100 45 45 45 45 45 1018 Steel -79 -40 0 23 100 16 25 53 65 81

Temperature (°C)

Shear %

Fracture Energy vs. Temperature

1018 Steel (Avg) -79 -40 0 23 100 9.6307692307692303 24.069230769230767 53.3 73 88.34615384615384 Standard Deviation (-) -79 -40 0 23 100 4.7824999999999998 7.9558600000000004 12.38965 5.90198 11.72139 Standard Deviation (+) -79 -40 0 23 100 22.872306249999998 63.295708339600004 153.5034271225 34.833367920400001 137.39098353209999

Temperature (°C)

Fracture Energy (ft-lb)