SU1206644A1 - Method of investigating mechanical properties of materials - Google Patents

Abstract

The invention allows high performance to determine the parameters for the transition of a material from a plastic to a fragile state by examining a single sample. The sample is stepwise heated with a powder at each step. During heating, the deformation rate is kept constant, and during the contractions it is increased until the appearance of a jump in the acoustic emission count rate, which is recorded during the loading process. When this jump occurs, the temperature and the jpocTb deformations that characterize the transition of the material from the plastic to the brittle state are determined. 2 Il. (/) with at) Od 4 4i

Description

The invention relates to a testing technique and can be used to study the mechanical properties of materials, in particular, to determine the parameters of the transfer of materials from a plastic to a brittle state.

The purpose of the invention is to increase the productivity of research and expand the functional capabilities by determining the strain rate corresponding to the transition of a material from a plastic to a fragile state.

FIG. Figure 1 shows a graph of acoustic emission count rate versus strain rate at various temperatures5 in FIG. 2 shows the dependence of the change in the onset of the Transition of a material from a plastic state to a brittle state as a function of temperature and deformation rate.

The method is as follows. in a way.

A sample of the test material is fixed in a test apparatus with varying strain rates, for example, in compression. Heated; the sample to a predetermined temperature T, corresponding to the beginning of the temperature range in which the parameters (temperature and formation rate) of the transition of the material from a plastic to a fragile state are determined. The heating temperature T of the sample is maintained for a certain time during which the sample is loaded with compressive loads, increasing the deformation rate from zero to, at which the acoustic emission count rate jumps. The jump of this parameter indicates the beginning of the transition of the material from the plastic to the fragile state at a given temperature T and the deformation rate.

After the appearance of a jump in the acoustic emission count rate, the shaping rate is kept constant, while simultaneously heating the sample by a specified amount to a temperature T. During a peak at this temperature, the sample deformation rate is increased from B, to 2 5 Р which is repeated an increase in the acoustic emission count rate indicating the beginning of the transfer of material from plastic

The state is brittle at a temperature Tj, and the deformation rate is E2. Further tests are carried out in the same way, by stepwise heating the sample in a given temperature range with a loop at each step, during which the deformation rate is increased to a jump in the acoustic emission count rate, while maintaining during heating constant deformation rate.

Thus, in the process of testing a single specimen, the temperatures Tj and strain rates characterizing the indicated transition are determined.

Example. Sample manufactured. Uranium dioxide dioxide heated

to a temperature T of 977 ° C, it is loaded with a compressive load, increasing the speed (formation from zero to 1.2 to 10, at which the acoustic emission count rate jumps, which indicates the beginning of the transition of uranium dioxide from plastic to brittle at temperature T, and speeds de

formation 6 (

Then heat up,

the sample to a temperature of T 1327 C. The speed of 6, the deformation during heating to this temperature is kept constant at 1, C. After the preset temperature was established, the deforming speed of 10 spraying to bg 8 with the second led to a repeated sharp increase in the acoustic emission counting rate, which indicates the transition of uranium dioxide from a plastic to brittle state at a temperature T and a deformation rate of g.

Claims (1)

Invention Formula A method for studying the mechanical properties of materials, which consists in heating a material, deforming, and determining the transition temperature of a material from a plastic to a brittle state, characterized in that in order to increase the productivity of research and enhance functionality by determining the strain rate corresponding to the transition material from plastic state to brittle, heating is carried out stepwise, holding at each stage, during heating the speed is deformed and kept constant, the acoustic emission count rate is measured during the test, the deformation rate is increased during exposures to a jump in the acoustic emmsin count rate, which corresponds to the beginning of the transition of the material from the plastic to brittle state, and at this moment the velocity is determined. warping. t, to 6, fo ten vd Wi t 2d 40  Cjfiuh  l-7 .2 Editor I. Nick Olaichuk Compiled by V. Grinenko Tehred A.Ach Order 8701/43 Circulation 778 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Branch PPP Patent, Uzhgorod, st. Project, 4 Proofreader A. Obruchar Subscription