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Material Science Memorandum

To: Dr. Mathew Cathell

From: Brandon Simon

Date: October 14, 2014Subject: Aluminum Alloy Mechanical ro!ertie"

Abstract

#he ob$ecti%e o& the lab wa" to determine the mechanical !ro!ertie" o& a certain aluminum alloy.

#hi" wa" done u"in' #iniu" Ol"en( )ni%er"al #e"tin' Machine. #he data &ound wa" u"ed in

determinin' *oun'+", "hear, and bul moduli, yield "tren'th and ultimate ten"ile "tren'th,

re"ilience and tou'hne"", and Den"ity. #he %alue" &ound were within an error o& about 10-.

Procedure

#o be'in, we u"ed a #iniu" Ol"en( )ni%er"al #e"tin' Machine )#M/, which mea"ure"

the &orce and di&&erence in len'th o& the material, and eten"ometer, which mea"ure" the !ercent"train. #he material, the Aluminum "!ecimen, wa" loaded into the )#M with the eten"ometer. At

the a!!roimate !oint o& de&ormation the eten"ometer wa" remo%ed &or the "a&ety o& the

eten"ometer. #he ten"ion wa" then a!!lied until &ailure. #he )#M &unction" by ha%in' the

"!ecimen attached to two !lat&orm" %ia clam!" and i" then !ut into ten"ion u"in' two "crewmechani"m" to lower the bottom !lat&orm. #he eten"ometer, which o!erate" by clam!in' on to

the "!ecimen !arallel to the ten"ion a!!lied, mea"ure" the chan'e in len'th and calculate" the

aial "train &rom the di&&erence. #he eten"ometer add" a hi'h de'ree o& accuracy &or the ela"tic

!ortion o& de&ormation. #he %alue" collected by the )#M wa" &orce / and !o"ition mm/, or

di&&erence in !o"ition. #he eten"ometer collected the "train -/ %alue".

Results and Discussion

YoungsModulus(GPa)

ShearModulus(GPa)

BulkModulus(GPa)

Density(g/cm^3)

YieldStrength (MPa)

ltimate!ensileStrength(MPa)

"esilience(#/m^3)

!oughness(#/m^3)

$alc %&'* *'*3% %%'*3 '&*%

3+,'*% 3-',+* ,'.-

3*'.&3&

ct %-' % %- '& &% 3,+ ,',. 01rr2 ,'.,. ,'&-* '+%& '+-- '%. *'-.+ ,,'+% 0Table 1

#he re"ult" &ound !aralleled the mechanical !ro!ertie" o& Aluminum 013# with a hi'h

de'ree o& accuracy. #able 1 demon"trate" the minimal error &ound between the calculated %alue"calc/ and the literature %alue" act/. #he only literature %alue not &ound wa" tou'hne"", due to the

more commonly u"ed &racture tou'hne"", a tou'hne"" determined by a material" tendency to ha%e

a crac !ro!a'ate.

rom the initial data collected5 &orce, !o"ition, and "train, &rom here on called S0, we

determined the "tre"" and "train that occurred on the aluminum "!ecimen o%er the cour"e o& the

te"t. #o do thi", the &ir"t %alue to be con%erted wa" &orce to "tre"". #he "tre"", &ound by thi"

e6uation5

7 8 9 A0 1/

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where i" the &orce, A0i" the cro"" "ectional, and 7 i" the "tre"" %alue. #he "train !ercent &rom S0

wa" then con%erted into actual "train by multi!lyin' it by 100. #he"e %alue", initially ne'ati%e

&rom "li!!a'e, were u"ed until the %alue" became ne'ati%e &or "econd time. #he "train wa" then

calculated %ia the !o"ition, u"in' the e6uation5

: 8 9 ; 2/with bein' the !o"ition, ; bein' the initial len'th o& the "!ecimen under ten"ion, and : bein' the

"train %alue. &or the collected data, howe%er, it wa"

determined that the %alue" were wildly %aried.#o com!en"ate, ba"ic "tati"tical analy"i" wa" u"ed

to eclude outlier" &rom the data collected when &indin' the a%era'e. #he >, ?.@ =a, wa" then

u"ed to determine the yield "tren'th %ia the 0.2- rule. A" "een by 'ra!h 2, the !oint o&

inter"ection i" mo"t clo"ely a!!roimated to 01 Ma.

#he "hear modulu" and bul modulu" were both &ound u"in' > and !oi""on+" ratio, , a

'i%en %alue that i" the ne'ati%e ratio o& the lon'itudinal "train to the aial "train. oi""on+" ratio i"

e6ual to 0.. #he e6uation" u"ed &or determinin' "hear modulu" and bul modulu" are5

8 > 9 21E // /

= 8 > 9 12// 4/

Fe"!ecti%ely.

#he ultimate ten"ile "tren'th wa" &ound by determinin' the hi'he"t !oint o& "tre"" acted

on the "!ecimen. #he %alue had a "li'htly more "i'ni&icant error o& G-, howe%er the Ma

di&&erence in the em!irical and actual %alue almo"t coincide" with the di&&erence in yield "tren'th,an error that maybe accounted &or by the "li!!a'e.

#he modulu" o& re"ilience and the tou'hne"" were both &ound u"in' "imilar method"5 e.'.

to &ind the %alue with a tra!eHoidal Fiemann "um.

#he den"ity wa" determined u"in' the %olume, I, and the ma"", M, in the e6uation5

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d 8 M 9 I G/

in which M i" e6ual to 4? ', and I i" e6ual to 1?.0G14 cm.

Conclusion

#he error &ound in mo"t ca"e" were minimal. Fe"ilience, )ltimate ten"ile "tren'th, andyield "tren'th where the only %alue" to e!erience a !ercent error beyond -. #he error in

re"ilience wa" mo"t liely de!endent on the error in yield "tren'th. #he error in yield "tren'th andultimate ten"ile "tren'th could be accounted &or a certain amount by "li!!a'e and error in the

)#M+" mea"urement o& !o"ition or &orce.

Appendix

Stre""

7 8 9 A0 1/

Strain

: 8 9 ; 2/

Shear Modulu"

8 > 9 21E // /

Bul Modulu"

= 8 > 9 12// 4/Den"ity

d 8 M 9 I G/

Graph 2

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