Thanks for the photos along with your question. Clearly the branch that is losing its bark is because it is dead. It looks to me that the tree is suffering from stress, which could have various causes. Hot, dry weather, lack of water, root damage, compacted soil, improper pruning to name a few. 

I don't expect the tree to die. Amur maples are tough trees and more likely to suffer from poor site conditions than a disease. Do you see any damage to the trunk near the ground? Do you see any unusual growths, i.e. bumps, fungus, cracks, or cankers? Stem girdling roots cause a tree to decline as it strangles the trunk cutting off circulation. Here are links to more information:

https://extension.umn.edu/planting-and-growing-guides/storm-damage-landscape-trees

I suggest pruning off any branches that are dead. Leaving as small of wound as possible. I would expect new sprout growth from the remaining trunk. 

Paul -Tree Care volunteer



That is a good sign that there is no damage to the trunk. I wish you good luck in keeping the tree.