What was the alloy of the shackle used to hold the "Little Boy" bomb in place on the Enola Gay bomber?

by Altomckee

My grandfather, rest his soul, had spoken in an interview that he created the an metal alloy strong enough to hold the bery heavy bomb. I can't find any information about online. His name is Arthur Breslow

Neurorational

Follow up question: do you know what company he worked for and did he have any connection to Zeppo Marx or Marman Products? (Zeppo Marx's company, Marman Products, made the Marman Clamps, which is variously said to have supported one or both A-bombs either in transport or possibly on the final delivery planes, although Marman Products wasn't necessarily involved with the development of the alloy.)