The general 'rule of thumb' is that metals running together should be dissimilar and one should be softer or weaker than the other.
There are some situations where the 'rule' can be broken fairly safely:
Brass running on brass, or bronze on bronze, is normally quite okay and sometimes with some bronzes it is not even necessary to use lubrication. The mechanism inside old clocks was often made from a bronze that did not require lubrication and oiling them could cause accelerated wear b ecause the oil collected dust.
Hardened steel running on hardened steel, with the proper type of lubrication is also okay; obviously because it occurs in gearboxes and transmissions in nmotor vehicles. But in this case the surface finish has to be very good and the correct lubricant is essential.
The reason for having differences in strength and softness is because whenever two metals are sliding past each other it is the high spots that hit. And extremely high contact pressures can occur betrween these high spots; high enough to create a hot spot at a temperature high enough that micro-welds can form. This is less likely to happen between dissimilar metals and when it does the weld fractures readily. Sometimes the fracture is in the harder metal, the localized high temperature hot spot that caused the micro-weld can make it brittle, when this happens the minuscule particle that breaks off embeds into the softer material and does not cause problems. Sometimes the weld tears out of the softer metal, but again this does not cause a problem because the fragment of softer metal gets smeared out into the surface roughness of the harder metal. This process of welding and breaking and smearing eventually results in the high spots in both metals being rubbed off or smeared out and this is the running in process.
However, when the two metals are identical or very similar things can go wrong very badly. The micro-welds still form, but now the material strength is the same on both sides. This means that there is a chance that tearing will occur on both sides and instead of a little particle breaking off and getting embedded in a softer material it is possible that a large particle, larger than the clearance between the moving parts, tears off and gets wedged in the clearance...causing more welding and tearing until everything just galls up solid.
It is possible to get some aluminum alloys that will run against each other okay. I think some of the high silicon casting alloys can run with some of the formable alloys; think about forged pistons running in an aluminum cylinder on cheap little engines. But I think trying to run 6061 against 7075 is risky. It is possible this combination would work okay if one or both was hard-coat anodized but some experimentation may be a good idea.