ИСТИНА

Article is describe research of natural fracture of circle specimens d01 = 5 mm and d02 = 4 mm from aluminum alloy D16T under working deformation temperature. 400ºС, stretching under creep by constant force with initial stress is σ0 = 33 MPa. There are to get increasing length of specimen – l(t), allocation diameters along specimen in any time – d(x, t), allocation of stress of specimen – (x, t) and other. There were researched different criterions of neck detection during high temperature natural experiments. Created criteria show that moment of neck formation happens not at end of lifetime, but before that. The moment of neck formation is 55-80% relatively lifetime, that appreciably higher theoretical approach. This result was get from natural experiment.