The creep behavior of single-crystalline Ni3Ge alloys

Abstract

eva, M. V. Gettinger, S. V. Starenchenko, UDC 539.376:666.24 and V. A. StarenchenkoThe creep of single-crystalline Ni 3 Ge alloys subjected to compression along the strain axis [001] has been investigated. The resulting creep curves have revealed low and high secondary-creep rates. Inverse hightemperature creep behavior has been observed.

Cottrell−Stokes Law for Ni3Ge Intermetallic Single Crystals with the [ 2 ¯ $$ \overline{2} $$ 3 4] Compression Axis

“…The experimental dependence of the stress jump Table 1. A comparison of the coefficient с 1 obtained from the experiments on the temperature variation (Table 1) with its value calculated from the formula 1 G с G ∆α ∆ = + α [15] using the data of direct measurements of the dislocation density [18] and of the temperature dependence of the shear modulus [19] (Table 2) crystals that reflect low rate of thermal strengthening for the cubic slip. On the other hand, the positive value of the coefficient с 1 and the negative value of the coefficient с 2 indicate the superposition of the normal and anomalous mechanisms of the deformation processes in the examined temperature interval.…”

“…As already indicated above, the coefficient с 2 was also negative (see Table 1). This means that, the same as for the octahedral slip [15,16], the stress jump attendant to temperature variation can be represented as a superposition of the normal and anomalous stress jumps:…”

“…The Ni 3 Ge alloy for which we performed extensive cycle of investigations [8][9][10][11][12][13][14] is among them. The study of the Ni 3 Ge single crystals with the L1 2 ordered superstructure demonstrated that the Cottrell−Stokes law was valid for samples deformed along the [001] [15] and [ 1 3 9] axes [16]. However, it is necessary to find whether this law is valid for other orientations and to elucidate conditions under which it is valid.…”

Thermoactive creep characteristics for single crystals of Ni3Ge alloy with different orientations

“…However, the creep properties of this alloy remain poorly studied. In [3][4][5][6][7][8], we studied the flow curves for different conditions of temperature and force and determined their features for single crystals of Ni 3 Ge intermetallic compound at different orien tations.…”

Modeling of macroscopic strain localization in alloys with the L12 structure

“…Strain localization bands caused by creeping in a single Ni 3 Ge crystal with the [⎯13 9] strain axis at a temperature of 918 K[32].…”