This issue is a variant of Avengers (Marvel, 2010 series) #1 [Standard Cover]. There exist further variants.
This cover sports the Heroic Age trade dress
Prologue and Chapter 1. Continued in New Avengers (Marvel, 2010 series) #1. Illustrations reprinted from Avengers Classic (Marvel, 2007 series) #1 and The Avengers (Marvel, 1963 series) #1.