Cause of metal deterioration in heating element coil

[Merlion]

I put a tumble dryer that had been used only a few times back in operation after a decade being completely out of service. Heating failed shortly after switching on. Checked the heating element and noticed that it is broken at a dozen locations. The spiral is very brittle and breaks easily when I touch it, even in a cold state.

This is obviously some sort of chemical deterioration proces that has taken place. What causes this deterioration?

 

[Baluncore]

It sounds more like metal fatigue. A filament may be annealed when heated and cooled, but time, cold or vibration may change the state of the metal to make it more brittle.
Was the drier transported, a long time after it was last heated ?
Was the drier stored near a source of vibration during those 10 years ?

 

[Merlion]

No the dryer was at the same location (store room inside house, region of moderate climate, room occasionally heated during winter) fully static, during this 10-year period.