According to the [Review of Particle Physics][1] (Section 33.7.4 of the 2014 edition) there are two main causes of radiation damage for electronic devices:

 

>  1. Bulk damage due to displacement of atoms from their lattice sites. This leads to increased leakage current, carrier trapping, and
> build-up of space charge that changes the required operating voltage.
> Displacement damage depends on the non-ionizing energy loss and the
> energy imparted to the recoil atoms, which can initiate a chain of
> subsequent displacements, i.e., damage clusters. Hence, it is critical
> to consider both particle type and energy.
>  2. Surface damage due to charge build-up in surface layers, which leads to increased surface leakage currents. In strip detectors the
> inter-strip isolation is affected. The effects of charge build-up are
> strongly dependent on the device structure and on fabrication details.
> Since the damage is proportional to the absorbed energy (when
> ionization dominates), the dose can be specified in rad (or Gray)
> independent of particle type.

The [review][2] is freely accessible and, although brief and technical, you can find more details there. Also, the review suggests to look at the [Handbook of Radiation Effects][3] for a detailed explanation on the matter. From what I can see from the ToC, there is also a chapter named *The interaction of radiation with shielding materials* that might answer your curiosity about mechanical damage.


  [1]: http://pdg.lbl.gov/
  [2]: http://pdg.lbl.gov/
  [3]: http://ukcatalogue.oup.com/product/9780198507338.do