Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MAT SCI 298 > Lecture 5 - Titanium Alloys > Flashcards

Lecture 5 - Titanium Alloys Flashcards

1
Q

What is CP-Ti?

A

commercial purity Ti

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the crystal structure of beta-Ti?

A

bcc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the crystal structure of alpha-Ti?

A

hcp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the density of ti?

A

4.5 g/cm3 (low)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the melting temperature?

A

1668C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the boiling point?

A

3287C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the Young’s Modulus of Ti?

A

110GPa (low)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the four types of Ti alloys?

A

alpha
alpha + beta
beta meta stable
beta stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why are Ti alloys used?

A

good specific tensile strength at elevated temperatures
excellent corrosion resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the density of Ti-6Al-4V?

A

4.429 g/cc (lower than normal titanium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which type of titanium is used for medical grade?

A

Ti-6Al-4V, extra low interstitials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does an increased amount of Al (alpha stabilizer) do?

A

increases beta transus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which elements have a neutral effect on Ti?

A

Sn, Zr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which elements have an alpha-stabilizing effect on Ti?

A

Al, O, N, C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which elements have an beta-isomorphous effect on Ti?

A

Mo, V, Ta, Nb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which elements have a beta-eutectoid effect on To?

A

Fe, Mn, Cr, Co, Ni, Cu, Si H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the Ti-Al-x alloys?

A

alpha and alpha + beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the Ti-transition-metal-based?

A

beta meta stable and beta stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Alpha alloys have a higher _____ than pure Ti

A

beta transus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Addition of oxygen can raise _______ 4x

A

yield strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Al-Sn additions are effective ________________

A

strengtheners

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

___________ values for Ti alloys are 2x higher than that of Al alloys

A

Klc (plane strain fracture toughness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a martensitic transformation?

A

diffusion-less solid-to-solid phase transitions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the angle needed to change BCC to HCP?

A

10.6 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Which phase is diffusion slower in?
alpha phase (hcp)
26
What does diffusion affect in AM
elemental partition
27
How do O and Al differ for AM?
powders have higher O and lower Al
28
What is the yield strength and ductility of AM Ti-6Al-4V?
yield strength is high, ductility is small
29
What are the five strengthening mechanisms for L-PBF in Ti64?
phase solid solute dislocation boundary pores
30
What happens to the tensile ductility when 90 degrees from build direction?
drops dramatically
31
voids play a role in _________ of PBF Ti64
necking and fracture behavior
32
Why are Ti alloys tough to print via L-PBF?
martensitic phase transformation during 3D printing
33
What challenges remain difficult to overcome?
impurities and pores
34
What does a majority of 3D printed Ti64 alloys have?
poor ductility
35
where are the studies of corrosion resistance and biocompatibility at?
ongoing
36
what limits aerospace applications for 3d printed Ti64 alloys?
elevated temperature properties (creep) and fatigue properties
37
What is BCC?
body centered cubic
38
What is FCC?
face centered cubic
39
What is HCP?
hexagonal close packing
40
What is unique about titanium phases?
multiple phases unlike steels
41
How does beta Ti compare with alpha Ti?
more ductile (alpha-Ti is brittle)
42
What are the properties of alpha + beta Ti?
mix of ductile and brittle
43
How does Ti do in low temperatures?
very good tensile strength
44
How does Ti compare in weight?
very light
45
What does ELI mean?
extra low interstitials (low oxygen levels)
46
What happens when you add too much Al?
creates brittle Ti3Al
47
Why do you want the beta transition temperature as low as possible?
avoid brittle material when cooling
48
What are the gamma and omega phases?
too brittle, shatter
49
What does alpha-stabilizing and beta-stabilizing mean?
the more of these elements you add, the more alpha/beta there is
50
What happens if you add too much beta-stabilizing elements?
heavier, lose corrosion resistance
51
what is the downside to beta Ti Alloys?
not as ductile as alpha + beta
52
What happens to the shear strength from beta to alpha?
introduces tan(10.6 degrees) = .187 shear strength (18.7%)
53
Which structures have the best close packing?
FCC and HCP
54
What shape has the best diffusivity?
BCC
55
What the cooling rates for the three quenching processes from highest to lowest?
water quench, air cooled, furnace cooled
56
What is the typical L-PBF cooling rate?
10^7 K/s
57
Why does iron get into the L-PBF build?
chamber is made of iron
58
Why is beta identified as pre-beta?
it used to be beta but now is alpha'
59
Where are impurities Fe and V located?
beta lines
60
higher energy input means what for V?
higher quenching rate, less time for V to diffuse
61
What does heat treatment do to V?
helps break it up
62
What happens to Ti when repeated heating and cooling?
twinning and dislocations
63
How does L-PBF/SLM compare to EBM in properties?
more alpha than beta, higher cooling rate, more yield strength, less ductility
64
What happens if you use an insufficient energy input on Ti?
reduce fatigue cycle
65
What are the optimal temperatures for annealing Ti5553?
300 and 800C

MAT SCI 298 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions