The ability to learn is a giftThe capacity to learn is a skillThe willingness to learn is a choice

- Rebec of Ginaz

Re: question from last class -Mech prop data for annealedplain carbon steels

0

10

20

30

40

50

60

70

80

90

100

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9% C

Yield or tensile stress

tensile

yield

tensile/yield

Also from last class:

Densities of some materials:

Al alloys 2.63-2.82 gm/cm3

steels 6.92-9.13Ti alloys 4.43-4.70Mg alloys 1.77-1.78Cu alloys 7.47-8.94glasses 2.4-2.7HDPE 0.96PMMA 1.22epoxies 1.25

Lotus versatile vehicle architecture system (VVA)

Al???

Almost completely "aluminum" - high pressure die-castings, stampings, and extrusions

Advanced Materials & Processes, July 2005, p 29

1050 1145 2014 2024 2219 2618 3003 3004 3105 4032 4043 5005 5052 5083 5154 5182 5262 5652 6010 6061 6262 6463 7005 7050 7072 7075 7175 7178 7475 7229

.

.

.

OK…..which "aluminum" is it?

1050 1145 2014 2024 2219 2618 3003 3004 3105 4032 4043 5005 5052 5083 5154 5182 5262 5652 6010 6061 6262 6463 7005 7050 7072 7075 7175 7178 7475 7229

OK…..which "aluminum" is it?

Alloy designation NOT same as steels

In fact, no carbon at all in ordinary Al alloys

Does NOT contain 0.61% carbon

1050 1145 2014 2024 2219 2618 3003 3004 3105 4032 4043 5005 5052 5083 5154 5182 5262 5652 6010 6061 6262 6463 7005 7050 7072 7075 7175 7178 7475 7229

Number Major alloy addition

1xxx -2xxx Cu3xxx Mn4xxx Si5xxx Mg6xxx Mg & Si7xxx Zn8xxx other

Here’s the scoop -

Al alloy containing 4.4% Cu (say 2024) can be heat treated to strength level much higher than that of pure Al

So, does alloying affect the properties?

Yield strength Tensile strength

Low-strength 30 ksi 60 ksi steel

Pure aluminum 5 ksi 13 ksi

Al alloy 2024-T4 47 ksi 68 ksi

Al alloy containing 4.4% Cu (say 2024) can be heat treated to strength level much higher than that of pure Al

So, does alloying affect the properties?

Yield strength Tensile strength

Low-strength 30 ksi 60 ksi steel

Pure aluminum 5 ksi 13 ksi

Al alloy 2024-T4 47 ksi 68 ksi

What’s this??

T4 designates a heat treatment (Al alloys only)

"solution heat-treated, quenched, and naturally aged to a substantially stable condition"

T4 designates a heat treatment (Al alloys only)

"solution heat-treated, quenched, and naturally aged to a substantially stable condition"

How do we know this works?…….& why does it make the material stronger?

How do we know it works?

We consult a road map for the material system

A portion of the Al-Cu"phase diagram"

We have a nomenclature problem

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A new concept - the solid solution

A single Cu-Zn alloy is formed

Then, where are the Zn atoms??