Advanced Materials Processing and Joining Laboratory [email protected] Tuesday, February 27 th, 2007 Friction Stir Welding of Bulk Metallic

Tuesday, February 27th , 2007

Advanced Materials Processing and Joining Laboratory

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Friction Stir Welding of Bulk Metallic Glasses

Presented

by

Lily MaMS Student- Materials Engineering and Science

Rakesh C. SuravarapuMS Student- Materials Engineering and Science

Stanley M. HowardProfessor, Department of Materials and Metallurgical Engineering

William J. ArbegastDirector, Advanced Material Processing Center

Katharine M. FloresAssistant Professor , Department of Material Science and Engineering

Ohio State University



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Objective

Establish a FSW processing window for BMG Vitreloy 106A to maintain its amorphous nature



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Fracture toughness –

~15 to 20 MPam1/2

Applications –

automotive and aerospace structures, biomedical devices, machinery structure materials, and sporting gears

Figure 1: Combination of strength and

Toughness compared with selected

engineering materials. (Flores, K.M et al. 2003 )

Background



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Materials

2.8Nb

10.3Al

12.8Ni

15.6Cu

58.5Zr

Atomic Percent Element

Composition of Vitreloy 106A

Figure 2 Time temperature transformation

diagram of the bulk metallic glass –

Vitreloy106A. (Hays, C.C et al. 2001)

Crystalline

Amorphous

200

Tg = 400 oC

Tliq = 830 o C

Tem

per

atu

re º

C

500

600

700

800

300

900

400



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0.39”

0.6”

0.39”

0.6”

1.84”

1.78”

Sample C

Sample BSample A

Samples and Campaign Conditions

Table 1: Summary of the campaign conditions

Preheated friction stir

welding

YesCCampaign III

Series of four linear friction stir

weldsNoCCampaign II

Friction stir plunging

NoBCampaign I

N/AN/AAReference

ProcessPreheated

Sample

Description



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Campaign I – Friction stir plunging

500RPM 800RPM

Friction stir plunged sampleSample B

CopperPlates

PCBNPin Tool

Clamping and weld setup

Two plunges on Sample B:500RPM and 800RPM

PCBN pin tool was used

Sample B was placed on thecopper plates for rapid cooling



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Campaign II – Friction stir welding (no preheating)Table 2: Processing parameters used in Campaign II

Pin Tool

Weld No.

Weld Length (inches)

Weld Speed

(in/min)

Spindle Speed (RPM)

Forge Depth

(inx10-3)

Plunge Rate

(in/min/s)

Forge Force

(pounds)Atmosphere

PCBN 1 1.00 1.0 500 5 0.130 882 Air

PCBN 2 0.65 1.0 500 15 0.130 950 Air

W-Re 3 0.35 0.5 300 10 0.130 2070 Argon

W-Re 4 0.85 0.5 800 10 - 16 0.065 647 Argon

Clamping and weld setup 1st & 2nd welds withoutArgon blanket



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3rd & 4th welds withArgon blanket

Weld-2

Friction stir welded sample

Weld-4

Weld-1

Weld-3 Weld-2

Campaign II cont’d



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Pin tool wearB

efo

reA

fter

PCBN 2 Weld 2

PCBN 1 Weld 1

W-Re 1 Weld 3

W-Re 2 Weld 4

W-Re 3 Pre-Heated

Weld

W-Re – 38002.0Pre-heated weld

W-Re – 28000.5Weld 4 (No Preheating)


PCBN – 25001.0Weld 2 (No Preheating)


Pin Tool UsedSpindle Speed

(RPM)Weld Speed

(IPM)Weld No.

Table 5: Processing parameters used in Campaign III



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Campaign III – Pre-heated friction stir welding


Pin Tool

Weld No.

Weld Length (inches)

Weld Speed (inches/min)

Spindle Speed (RPM)

Forge Depth

(inches)

Plunge Rate(inches/min/sec)

Forge Force (pounds)

W-Re 5 1.0 2.0 800 0.010 0.065 2000

Quenching with Liq Nitrogenafter the weld

Weld-5Friction stir welded sampleClamping and weld setup

Pre-heating plate



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Pin tool wearB

efo

reA

fter

PCBN 2 Weld 2

PCBN 1 Weld 1

W-Re 1 Weld 3

W-Re 2 Weld 4

W-Re 3 Pre-Heated

Weld

W-Re – 38002.0Pre-heated weld





Pin Tool UsedSpindle Speed

(RPM)Weld Speed

(IPM)Weld No.




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Campaign II – Surface XRD

Scan 1

Scan 2

Scan 3

Scan 4Scan 5Scan 6

Scan 7Scan 8Scan 9

Friction stir weldedsample

Weld-2

Weld-4

Weld-1

Weld-3 Weld-2

1 2 3

9 87

645

Weld No.Pin Tool

IPM RPM

Weld #1PCBN –

1500 1.0

Weld #2PCBN –

2 500 1.0

Weld #3 W-Re 300 0.5

Weld #4W-Re 800 0.5

Two-Theta (deg.)

Inte

nsit

y (

Cou

nts

)



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Weld-5

10

Spot 10

Campaign III – Surface XRD Weld 5

Weld No.Pin Tool

IPM RPM

Pre-heated Weld #5

W-Re 800 2.0



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DSC Campaign II and III – 450oC to 550oC

100% Crystalline

95% Crystalline

59% Crystalline

57% Crystalline

62% Crystalline

29% Crystalline

0% Crystalline

PercentCrystalline

21.22 J/g

25.02 J/g

56.4 J/g

68.01 J/g

70.5 J/g

96.5 J/g

102.1 J/g

Parent Metal

Weld #2 – Campaign II


Weld#5 – Campaign III



Crystallized Sample

Exo UpTemperature (oC)



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Weld 2:

Off weld / On weld

Weld 5:

Off weld / On weld



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Comparison of crystallinity

XRD LocationCrystallinity, (%)

Surface XRD

Cross section XRD

DSC

Crystallized Bulk Metallic Glass Sample 100 100 100

Weld 4 (Campaign II) 60 53 42



Weld 5 (Campaign III - Pre Heated) 51 61 56

Weld 2 (Campaign II) 35 24 6.9

Amorphous Bulk Metallic Glass -Parent Metal 0 0 0



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•Vitreloy can be plasticized by friction stir plunging while maintaining amorphous

condition

•Pre-heating resulted in superior plasticization

•Process window appears to have 800 RPM and 2 IPM (initially)

•Pre-heating with quenching is recommended primarily for the weld quality and

pin tool life

Conclusions

Documents

Advanced Materials Processing and Joining Laboratory [email protected] Tuesday, February 27 th, 2007 Friction Stir Welding of Bulk Metallic