scholarly journals Evolution of Structural-Phase States in TiNi Surface Layers Synthesized by Electron Beam Treatment

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
L. L. Meisner ◽  
A. I. Lotkov ◽  
Yu. P. Mironov ◽  
A. A. Neyman
Keyword(s):  
Internal Stress ◽  
Intermediate Layer ◽  
Martensite Transformation ◽  
Stress Concentrator ◽  
Structural Phase ◽  
Martensite Phase ◽  
Relaxation Processes ◽  
Surface Layers ◽  
Tini Surface ◽  
B2 Phase

The paper presents the results of X-ray diffraction analysis of nonequilibrium structural and elastic stress states in TiNi surface layers irradiated by low-energy electron beams. It is found that a surface layer with a mixed (2D columnar and 3D equiaxial) submicrocrystalline structure is formed on the irradiated side of the TiNi specimens, and the volume fractions of the two structure types depend on the beam energy parameters and number of pulses. The B2 phase synthesized in the layer is characterized by lattice microstrain due to stresses of the first and second kinds (εI≈±1%,εII=0.25%), and the layer as such is an internal stress concentrator for underlying layers of the material. In the intermediate layer beneath the stress concentrator, relaxation of irradiation-induced internal stress takes place. It is shown that the main mechanism of the relaxation is partialB2→B19′martensite transformation. TheB19′martensite phase in the intermediate layer decreases the microstrain in the conjugate B2 phase. The thickness of the layer in which the relaxation processes develop through theB2→B19′martensite transformation is 10–15μm.

Gradient Structures and Internal Stress Fields in Surface Layers of Products Made of Steel 0.35C-1Cr-1Mn-1Si after Turning

2014 ◽  
Vol 1013 ◽  
pp. 170-175 ◽  
Author(s):  
Aleksandr Smirnov ◽  
Nikolai Ababkov ◽  
Aleksandra Glinka
Keyword(s):  
Heat Treatment ◽  
Internal Stress ◽  
Structural Phase ◽  
Nondestructive Method ◽  
Stress Fields ◽  
Surface Layers ◽  
Acoustic Characteristics ◽  
Phase Condition ◽  
Internal Stress Field

The effect of different cutting (mechanical heat treatment) on the structural-phase condition and the internal stress field in the surface layers of the product is considered in the article. The regularities of acoustic characteristics depending on the parameters of the structure and stress for the development of nondestructive method for assessing the quality of the surface layer are identified

scholarly journals Behavior of Inelastic and Plastic Strains in Coarse-Grained Ti49.3Ni50.7(at%) Alloy Deformed in B2 States

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 741
Author(s):  
Dorzhima Zhapova ◽  
Victor Grishkov ◽  
Aleksandr Lotkov ◽  
Victor Timkin ◽  
Angelina Gusarenko ◽  
...  
Keyword(s):  
Martensite Transformation ◽  
Elastic Moduli ◽  
Inelastic Strain ◽  
Martensite Phase ◽  
Coarse Grained ◽  
Internal Stresses ◽  
Plastic Strains ◽  
Torsional Strain ◽  
Interphase Boundaries ◽  
B2 Phase

The regularities of the change in inelastic strain in coarse-grained samples of the Ti49.3Ni50.7 (at%) alloy are studied when the samples are given torsional strain in the state of the high-temperature B2 phase. During cooling and heating, the investigated samples underwent the B2–B19′ martensite transformation (MT); the temperature of the end of the reverse MT was Af = 273 K. It was found that at the temperature of isothermal cycles “loading-unloading” Af + 8 K, when the specimen is assigned a strain of 4%, the effect of superelasticity is observed. With an increase in the torsional strain, the shape memory effect is clearly manifested. It is assumed that the stabilization of the B19′ phase in unloaded samples is due to the appearance of dislocations during deformation due to high internal stresses at the interphase boundaries of the B2 phase and the martensite phase during MT. The appearance of dislocations during the loading of samples near the temperatures of forward and reverse MT can also be facilitated by the “softening” of the elastic moduli of the alloy in this temperature range. At a test temperature above Af + 26 K, the superelasticity effect dominates in the studied samples.

Influence of material parameters on 2D-martensitic transformation based on the phase-field finite-element method

2019 ◽  
Vol 116 (6) ◽  
pp. 614
Author(s):  
Li Chang ◽  
Gao Jingxiang ◽  
Zhang Dacheng ◽  
Chen Zhengwei ◽  
Han Xing
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Phase Transformation ◽  
Martensitic Transformation ◽  
Phase Field ◽  
Martensite Transformation ◽  
Transformation Process ◽  
Martensite Phase ◽  
Phase Field Method ◽  
Element Method

Obtaining an accurate microscopic representation of the martensitic transformation process is key to realizing the best performance of materials and is of great significance in the field of material design. Due to the martensite phase transformation is rapidly, the current experimental is hard to capture all the information in the Martensite phase transformation process. Combining the phase-field method with the finite-element method, a model of martensitic transformation from a metastable state to a steady state is established. The law of a single martensite nucleus during martensitic transformation is accurately described. By changing the key materials that affect martensite transformation and the phase-field parameters, the effects of the parameters on the single martensitic nucleation process are obtained. This study provides an important theoretical basis for effectively revealing the essence of martensite transformation and can determine effective ways to influence martensite transformation, obtain the optimal parameters and improve the mechanical properties of such materials.

scholarly journals STRUCTURAL AND PHASE CHANGES OF THE SURFACE LAYERS OF HEATRESISTANT MULTICOMPONENT COATING OF ION-PLASMA COATING Ni-Cr-Al-Y AFTER MODIFICATION BY HIGH-CURRENT ELECTRON BEAMS MICROSECOND DURATION

2020 ◽  
Vol 17 (34) ◽  
pp. 459-468
Author(s):  
Oksana A BYTSENKO ◽  
Igor G STESHENKO ◽  
Vladimir A PANOV ◽  
Victor V TISHKOV ◽  
Alexey B MARKOV
Keyword(s):  
Electron Beams ◽  
Structural Phase ◽  
Plasma Coating ◽  
Phase Changes ◽  
High Current ◽  
Surface Layers ◽  
Heat Resistant ◽  
Ion Plasma ◽  
Current Electron ◽  
High Current Electron

The development of aerospace engineering and mechanical engineering directly depends on the development of new metal materials and advanced technologies. The problem of creating materials and their types of processing to increase the level of operational properties is relevant in connection with the complication and tightening of working conditions of modern technologies. One of the most important tasks of contemporary aircraft construction is to increase the operational properties of the surface layer. The purpose of the article is to elucidate the effect of high-current electron beams of microsecond duration on changes in the surface layers of the heat-resistant multicomponent ion-plasma coating Ni-Cr-Al-Y under various conditions. Using a complex of metallophysical research methods, the physicochemical and structural-phase states of the surface layer were studied before and after modification of the samples. These samples were coated with heat-resistant condensed ion-plasma coatings of three different compositions using nine high-current electron beams in 9 modes with different values of electron energy and number of pulses in the selected interval of electron energy. An analysis of the structural phase changes occurring during modification was carried out. Cylindrical samples of targets made of heat-resistant nickel alloy ZhS36 coated with ion-plasma condensed multicomponent coating SDP-2 + VSDP-16. These samples were used according to serial technology, both with subsequent modification using highcurrent electron beams and without modification. It was found that chromium in the initial state is unevenly distributed: chromium is present in the particles; the matrix is depleted in chromium. The research results can be useful for scientists to study the properties of heat-resistant multicomponent ion-plasma coatings Ni-Cr-Al-Y and the effect of high-current electron beams on it, as well as for the manufacture of more heat-resistant materials in aerospace engineering and mechanical engineering.

scholarly journals Changes in structural-phase state and physicochemical properties of tungsten-free TIC-TiNi hard alloys after various types of ion-beam treatment

2021 ◽  
pp. 5-9
Author(s):  
V. V. Akimov ◽  
◽  
A. M. Badamshin ◽  
S. N. Nesov ◽  
S. N. Povoroznyuk ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Phase State ◽  
Ion Beam ◽  
Structural Phase ◽  
Experimental Methods ◽  
Hard Alloys ◽  
Surface Layers ◽  
Initial State ◽  
Structural Phase State ◽  
Ion Beam Treatment

Using experimental methods of analysis, the morphology, elemental composition and chemical state of hard alloys of the «TiC-TiNi» system in the initial state and after various types of ion-beam treatment have been investigated. It is found that the effect of a continuous ion beam leads to an increase in the microhardness of the investigated alloys by 10–12 %. When samples are irradiated with a pulsed ion beam, as a result of destruction of surface layers, the microhardness value decreases by 20 %, as a result of which this type of modification is not preferable for alloys of the TiC-TiNi system

Features of damage and modification of surface layers of Al and its alloys by powerful energy flows in a plasma focus device

2021 ◽  
Vol 9 ◽  
pp. 34-52
Author(s):  
V. N. Pimenov ◽  
◽  
S.A. Maslyaev ◽  
Keyword(s):  
Surface Layer ◽  
Plasma Focus ◽  
Phase State ◽  
Structural Phase ◽  
Pulsed Laser ◽  
Plasma Focus Device ◽  
Deuterium Plasma ◽  
Surface Layers ◽  
Pulsed Laser Radiation ◽  
Structural Phase State

The results of the analysis of damageability and modification of the structural-phase state of the surface layers of aluminum and its alloys by powerful flows of fast high-energy ions and high-temperature plasma in Plasma focus devices, as well as using pulsed laser radiation. Pure Al, an alloy of the Al – Mg – Li system, a duralumin alloy, and a composition of a ceramic coating Al2O3 on an Al substrate are considered. It is shown that in the regime of Al irradiation with a power density of q ≈ 106 – 107 W/cm2 in the nano- and microsecond range of pulse durations, ultrafast crystallization of melted surface layer occurs with the formation of a wavy surface relief and the structural fragments of sub-microcrystalline and nanoscale size. After the action of deuterium plasma flows on a duralumin alloy tube located along the axis of the Plasma focus device a modification of the structural-phase state of the alloy is observed: the initial two-phase state of an αAl-solid solution of copper in aluminum and inclusions of the second phase of CuAl2 became fine-grained and single-phase due to the dissolution of CuAl2 particles in the melt. Irradiation of an alloy of the Al – Mg – Li system containing (wt %) 2 % Li and 5 % Mg at q = 5·106 W/cm2, t = 50 – 100 ns after four pulsed impacts of fast ions and deuterium plasma led to the modification the structural-phase state of the surface layer of the alloy, associated with an increase in the content of magnesium oxide and a decrease in the crystal lattice parameter of the Al-based solid solution. The formation of spherical cavities due to the evaporation of lithium into the internal micropores of the surface layer was also found. The low damage and structural stability of Al2O3 ceramics on an Al substrate under beam-plasma impacts in plasma focus device with a radiation power density q ≤ 108 – 109 W/cm2 in the nano- and microsecond range of pulse duration is noted. At the same time, the Al2O3/Al composition was unstable to pulsed laser radiation in the free-running mode (q = 105 – 106 W/cm2, t = 0.7 ms) and Q-switch mode (q = 107 – 108 W/cm2, t = 80 ns). In both cases the coating peeled off from the substrate.

scholarly journals The Effect of Drawing Deformation Rate Induced Inhomogeneous Local Distortion on Phase Transformation of 304H Stainless Wire

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1304
Author(s):  
Qinhua Xu ◽  
Zhixian Peng ◽  
Jianxin Zhu ◽  
Mingyang Li ◽  
Yong Zong ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Transformation ◽  
Heat Generation ◽  
Martensite Transformation ◽  
Local Strain ◽  
Cold Drawing ◽  
Element Distribution ◽  
Martensite Phase ◽  
Single Strain ◽  
Area Reduction

The micro/macro magnetic properties, local element distribution, martensite transformation, and mechanical properties of 304H stainless wires are determined for two cold drawing chains. Finite element simulations are used to analyse the local strain and heat generation. The results show that there is obvious inhomogeneity in the magnetic properties, strain/stress relationship, and strain-induced heat within the drawn wires. Comparing wires with the same total strain, a larger area reduction of previous drawing processes contributes to a higher volume of the martensite phase, while a smaller area reduction of the first process results in an inhibited phase transformation. A higher single strain in the first drawing process leads to additional heat generation at the subsurface of the wire, which would eventually retard the martensite transformation. The inhomogeneous deformation-induced differences in the grain size affect the stability of austenite and transform the final martensite.

The Study of Ultrasonic Dynamic Elastic Modulus of TiNiFe Shape Memory Alloy in Heating Process

2009 ◽  
Vol 79-82 ◽  
pp. 1699-1702
Author(s):  
Xiao Peng Gao ◽  
Fu Shun Liu
Keyword(s):  
Phase Transformation ◽  
Elastic Modulus ◽  
Test Temperature ◽  
Martensite Transformation ◽  
Martensite Phase ◽  
Austenite Phase ◽  
Dynamic Elastic Modulus ◽  
Heating Process ◽  
Static Tensile ◽  
Tensile Elastic Modulus

The phase transformation characteristics, the dynamic elastic modulus and the static tensile elastic modulus of Ti50Ni47.5Fe2.5 alloy were investigated. It is found that, the two mutations in the dynamic elastic modulus is caused by reverse martensite phase transformation and austenite phase transformation respectively; Static tensile test can not reflect the intrinsic elastic modulus when the test temperature is close to martensite transformation temperature(Ms). The static elastic modulus and the dynamic elastic modulus have the same trend when the test temperature is enough higher than Ms.

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