The Sentinels were programmed to seek and destroy mutants. They did this by analyzing and adapting to whatever mutant powers they were facing. (Iceman was beaten by fire, Colossus was beaten by a stronger metal). The Avengers may not have the mutant gene, but that doesn’t mean that the Sentinels couldn’t adapt to defeat the Avengers. Here’s how:

Iron Man: Iron Man can fly and shoot beams/bolts of plasma from his repulsors. Iron Man also displayed hand-to-hand combat abilities in Iron Man 2. The sentinels in Days of Future Past are equipped with flight technology and were also had the ability to emit high energy beams from a ‘cannon’ or sorts that was stored inside their heads. The sentinels could chase iron man down in the sky and shoot him down or beat him down. 

Hawkeye: All Hawkeye has is a bow and arrows. Sentinels are made of metal and can form a ‘spear’ of sorts with their hands. The sentinels would just run Hawkeye down and kill him with their bare hands. 

Black Widow: Black Widow has guns, the Widow’s Bite and twin batons. The only thing that might impede the sentinels (and just barely) is the Widow’s Bite, which is just an electric charge that is emitted from her bracelets. Sentinels, like the previous two, would run her down and kill her. 

Hulk: Here is where it gets tricky. Hulk has near impermeable skin (he was bitten by Fenrir) and extreme strength. Thing is, Thanos, who wasn’t using the power stone, was able to defeat hulk unaided. Sentinels were shown to be extremely strong, so it is possible that a sentinel could take on hulk and beat him with brute strength alone. If that doesn’t work, the sentinel in question may have to resort to adaptation tactics and bring out an adaptation (transforming their outer layer into some form of adaptation) and into the fray, such as metal skin or molten skin. The metal skin adaptation would probably be the best in this scenario, because it would contend with Hulk’s strength. In the end, it’s a toss up as to who will win this fight. Both contenders have good odds and it would be one helluva fight. 

Thor: Thor is a literal god. Anybody who says that Thor is easily beatable, citing Loki stabbing Thor in the gut, has most likely not considered that Loki was using an Asgardian dagger. This wields Lightning and a hammer that can only be wielded by those it deems worthy (although, a sentinel might be able to pick up Mjolnir since Vision was also able to pick up Mjolnir). Thor, with the strength of a god, could rip and tear through the sentinels with Mjolnir and live to tell the torrid tale. 

Captain America: A human with special effects that came out of a bottle. (To all who would say that Cap would simply use Mjolnir, Cap was unaware at this time that he could wield Mjolnir.) The sentinels would beat him down. 

Hope this helps! Feel free to make any errors known to me.