While the intergranular failure problems noted above are sometimes severe, they are rarely the cause of major service failures ( in structural steels, for example ), as suitable safety margins are included in the designs.
32.
An example of such texture, related to fractioned crystallization, is intergranular ( also known as intercumulus ) textures that develop wherever a mineral crystallizes later than the surrounding matrix, hence filling the left-over interstitial space.
33.
The principle of effective stress, introduced by Karl Terzaghi, states that the effective stress " ? "'( i . e ., the average intergranular stress between solid particles ) may be calculated by a simple subtraction of the pore pressure from the total stress:
34.
Perhaps the greater concern is that with the development of new technologies and materials with new and more extensive mechanical property requirements, and with the increasing impurity contents as a result of the increased recycling of materials, we may see intergranular failure in materials and situations not seen currently.
35.
In the SiC / Al 2 O 3 system, for example, it is widely known and accepted that the addition of SiC particles to the Al 2 O 3 matrix results in a change of failure mechanism from intergranular ( between grains ) to intragranular ( within grains ) fracture.
36.
Putting aside some of the well known facts about deposit phosphorus vs various properties, i . e . hardness or corrosion resistance that we will cover a bit later, deposits with a high degree of amorphous composition are free of grain boundaries, which typically act as sites for intergranular corrosion commonly encountered in crystalline deposits.
37.
Furthermore, results indicate that microscopic pores in sintered ceramic nanomaterials, mainly trapped at the junctions of microcrystalline grains, cause light to scatter and prevented true transparency . it has been observed that the total volume fraction of these nanoscale pores ( both intergranular and intragranular porosity ) must be less than 1 % for high-quality optical transmission.
38.
High-strength aluminium alloys such as the Duralumin-type alloys ( Al-Cu ) which depend upon precipitated phases for strengthening are susceptible to intergranular corrosion following sensitization at temperatures of about 120 �C . Nickel-rich alloys such as Inconel 600 and Incoloy 800 show similar susceptibility . steam generators, or as a result of subsequent welding of the formed structure.
