Improved Creep Resistant Zinc Alloys

1
Improved Creep Resistant Zinc Alloys

• Jeffery Allen
• Kiera Kampe
• Eric Vincent
• Advisor C.L. White
• Sponsor Eastern Alloys
• Collaborator Brillcast

2
Outline

• Background
• Compositions
• Casting
• Testing
• Results
• Conclusions

3
Background

• Eastern Alloys is investigating creep properties
  of die-cast zinc alloys
• Economical advantages
• Potential savings of 600,000 in manufacturing
  costs
• Previous research done by CSIR in South Africa

4
Determining Compositions
5
Compositions

• Compositions below are alloys cast in first
  casting trial.

6
Casting
Creep Tensile Testing Bar
Flow Length Bar
Charpy Bar
7
Creep Testing

• What is creep
• Temperature 140C
• Constant load 31 MPa

• Time to 1 Strain
• Time to Failure

8
Problems

• Temperature control
• 140/-2C ASTM low temperature creep test
  standard
• Initially we had 8C variation
• Solutions
• Baffles
• Additional heat zones

9
Scanning Electron Microscopy(SEM)
ZA-8 10um scale bar
Alloy1 10um scale bar
Alloy5 10um scale bar
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Energy Dispersive X-ray Spectroscopy (EDS)

• Used to determine the phases present

ZA8, scale bar 60µm
Alloy 5, scale bar 60µm
Alloy 1, scale bar 60µm
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Tensile Testing
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Impact Testing
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Hardness
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Creep Results

• ZA8-135 Computer error stopped test before
  recording time to failure.
• Al5-369 Stopped before failure at test max of
  160hrs

160.0 Maximum run time, test was stopped
15
Metallography
Before creep (Tensile Samples)
ZA-8 123, scale bar 20µm
Alloy 1-234, scale bar 20µm
After Creep
ZA8-131, scale bar 20µm
Alloy1-204, scale bar 20µm
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Conclusions

• Alloy1 and Alloy 5 show improved creep resistance
  compared to ZA-8
• The improved creep resistance may be due to the
  increase in Cu
• Additional testing is needed to further
  understand the creep mechanisms

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Questions?