Creep and cavity growth under multiaxial stresses

Abstract

A consideration of cavity growth by the acquisition of vacancies diffusing along grain boundaries in a polycrystalline material under stress at elevated temperatures leads to the evaluation of the influence of a multiaxial stress system on cavities on grain boundaries at any angle to the principal stresses. From this, the special features are examined of the form of creep process that operates to accommodate the progressive increase in volume of the growing cavities and conditions are determined where it may produce a creep strain exceeding that caused by the more common creep processes that are independent of cavity growth. In making these comparisons, it is important to take into account the major differences of the form of creep to accommodate cavity growth from other creep processes because it does not operate under conditions of constant volume.