T:SCC Season 2x07: "Brothers of Nablus" (spoilers)

[Starglider]

Losing a major stockpile of coltan to make hyperalloy with and making use of a substitute would explain why the recent batch of Terminators have been observed to be physically inferior to Cameron and the early T-888's (Cromartie, Carter, and Vick).

I find this unlikely. Cameron specifically stated that the reason for switching from titanium-based alloys to tantalum-based alloys is heat resistance. The melting point of titanium is 1668°C, but the melting point of tantalum is 3017 °C. Tantalum is about 50% stronger than titanium by cross-sectional area, but it is four times as dense, so solid tantalum would be a little over a third as strong as titanium in weight-constrained applications (which terminators almost certainly are). Normal coltan is mostly tantalum; but in theory terminators could use the other main component instead; niobium has a melting point of 2477 °C, is about twice as dense as titanium and is slighly weaker by volume, only slightly better than tantalum at a significant loss in heat resistance.

Of course terminators are not made out of elemental metal, they are made out of sophisticated (quite likely nanostructured) alloys, but based on my limited understanding of materials science I think the basic point stands. Skynet almost certainly made the switch in order to resist plasma weapons fire and the skeletal strength is either lower (for conventional alloys) or equivalent (e.g. if the metal just provides a bulk filler for a carbon nanotube composite).

Finally while this is relevant to the 'punch power cell out of chest' scene, it probably isn't relevant to cameron's fight with the other terminator. Any physical weakness there seemed to be in the joints and actuators, not in the main skeletal structure or armoring.

[Anguirus]

For more entries in the "how durable are Terminators" file, I submit the final battle in T1. Reese is in the middle of bleeding to death and can barely stand upright, but still knocks the Terminator in the head so hard that it deforms some of the lighter supports and forces it into an angle that would be impossible on a human. Then, he destroys its lower half with a pipe bomb, and while it kept on coming, its "hip" area was shredded and sent debris flying everywhere.

[Shroom Man 777]

Did it actually deform the Terminator's components? In T2, the Terminator's head withstood beatings far worse than that of a bleeding man wailing on him with a stick.

The Terminator moved its head to an angle impossible on a human to absorb the blow. We've seen Terminator do this to blows to the head, even blows from mental hospital workers with broken arms in casts.

[Anguirus]

In T2, the Terminator's head withstood beatings far worse than that of a bleeding man wailing on him with a stick.

His skull certainly did. I'm positive that it's specially reinforced to prevent a strong human with an axe from scoring a kill. It's impossible to tell if any internal components were stressed or damaged, though.

The Terminator moved its head to an angle impossible on a human to absorb the blow. We've seen Terminator do this to blows to the head, even blows from mental hospital workers with broken arms in casts.

I've never read the scene that way, it looks as if Reese is simply bashing the head aside. Obviously, serious damage is not sustained regardless.

[Shroom Man 777]

In T2, the Terminator's head withstood beatings far worse than that of a bleeding man wailing on him with a stick.

His skull certainly did. I'm positive that it's specially reinforced to prevent a strong human with an axe from scoring a kill. It's impossible to tell if any internal components were stressed or damaged, though.

I think the head was slightly deformed, and there was definitely internal damage. But it shows that it takes more than some skinny bleeding dude with a stick to damage a Terminator's brain. You need a skinny liquid metal dude with a much larger stick (an I-bar) to damage a Terminator's brain.

The Terminator moved its head to an angle impossible on a human to absorb the blow. We've seen Terminator do this to blows to the head, even blows from mental hospital workers with broken arms in casts.

I've never read the scene that way, it looks as if Reese is simply bashing the head aside. Obviously, serious damage is not sustained regardless.

I mean, the Terminator didn't really move its head, but it didn't resist and it just allowed the force of Reese's blow (and the force of the mental hospital guard) to shove its head around since there was no danger of sustaining any damage from Reese's stick (and the guard's casted hand) whatsoever.