You've got to ride further out from the edge of the road.
I have several totally blind bends on my commute. For these I'm usually almost on the centre line if there is one. If not I will be right in the middle so there's no room to get past. It gives me a better view of what might be coming towards me and it makes the driver behind have to go completely onto the other side of the road to get past. As that will put them directly facing anything that might be coming in the other direction, they tend to hold back.
Sometimes this doesn't work and I can usually sense when they are still going for the overtake - listen to the engine and tyre noise. Look behind so that they know you have seen them and block with your right arm straight out to the side with palm facing backwards to signal "Stop". Now they are faced with not quite half the road width to squeeze into. Don't leave it till the last second though. Be assertive and get in with the block (when you need it) before they have fully committed to the pass.
When you think it's safe for an overtake, pull back towards the side to give then room to pass safely (on your terms). Oh, and give them a friendly wave of thanks as they go past - it confuses the hell out of them!
If it's a commute, you and the car drivers are doing the same thing every day at the same time. It doesn't take long for them to learn what's going on and will start to hold back for the few seconds needed.