About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Lightweight Composites, Materials, and Alloys
|
| Presentation Title |
An investigation of the effects of hydrogen from casting water on cold-cracking of 7xxx Al alloys |
| Author(s) |
Jason Kramer, P. Chris Pistorius |
| On-Site Speaker (Planned) |
Jason Kramer |
| Abstract Scope |
During the direct-chill casting of 7xxx-series aluminum alloys employed in the aerospace industry, ingots experience thermal gradient-induced tensile stress, which can result in cold cracking after solidification. While cold cracking is generally attributed to defects during casting of brittle as-cast ingots, the presence of hydrogen in the alloy and water from cooling secondary cooling suggests that hydrogen embrittlement may play a role.
As-cast 7xxx Al samples from cold-cracked and non-cold cracked ingots were tested for both tensile and fracture toughness properties. The as-cast samples demonstrated a combination of brittle and ductile fracture, with brittle fracture following secondary phases. For comparison, additional samples were exposed to 100 °C casting water to promote hydrogen evolution before testing. Hydrogen content and surface reactions were investigated after exposure, and electrochemical behavior in casting water at 95 °C was quantified. The impact of hydrogen exposure on ductility and fracture toughness will be explored. |