Mutation of vacancies to divacancies by helium trapping in molybdenum effect on the onset of percolation

Vacancy mutation by (about six) trapped helium atoms — as has been observed in molybdenum — reduces the vacancy concentration, at which interconnecting paths for the helium begin to form, from 16 to 10% in b.c.c. materials. This follows from percolation studies which include this mutation effect.