An electrical current which alternately travels in either direction in a Current conductor. In 60 cycles per second (60 Hz) AC, the frequency used in the U.S.A., the current direction reverses 120 times every second.

A test specimen with the reduction section composed wholly of weld metal.

Adding a metal or alloy to another metal or alloy.

Change from one crystal structure of a metal to another that has different physical properties.

A material in which the atoms are capable of transforming into two or more crystalline structures at different temperatures.