Axel is widely considered the #1 free alternative for the Iron Man 3 and Age of Ultron title cards. It features wide proportions and a very mechanical "cut" on the edges of letters like "A" and "W."
If you want the "official" corporate feel, the logo designers pulled inspiration from real-world aerospace giants. Lockheed Martin: The Stark Industries logo is famously modeled after the Lockheed Martin Font Match: The closest professional typeface is Benton Sans Extra Condensed Black (used for the Marvel logo) or Helvetica Bold Modification: stark industries font free downl work
The original Stark Industries logo is not a single downloadable font but a custom design modeled after the logo of the real-world defense contractor Lockheed Martin Axel is widely considered the #1 free alternative