The Powder Metallurgy Processes Influencing the Fine Structure and Phase Composition TiC-NiTi Alloys

MICC 90 ◽  
1991 ◽  
pp. 1292-1301
Author(s):  
Peter Burkov
Keyword(s):  
Fine Structure ◽  
Phase Composition ◽  
Powder Metallurgy ◽  
Niti Alloys

Study on Preparation of Gradient Porous NiTi Alloys by Powder Metallurgy Method

2011 ◽  
Vol 299-300 ◽  
pp. 671-674
Author(s):  
Qiang Li ◽  
Jing Yuan Yu ◽  
Guo Chao Qi
Keyword(s):  
Phase Composition ◽  
Elastic Modulus ◽  
Powder Metallurgy ◽  
Porous Materials ◽  
Niti Alloy ◽  
Powder Metallurgy Method ◽  
Compressive Properties ◽  
Niti Alloys ◽  
Porous Niti ◽  
Tini Phase

Gradient porous NiTi alloys were fabricated by powder metallurgy method using NH4HCO3as space-holder. The effect of content and distribution of NH4HCO3on pore characteristic, phase composition and compressive properties was studied. The results showed the content of TiNi phase increased with the decrease of the content of NH4HCO3. When the distribution of NH4HCO3varying form 12wt%-12wt%-12wt% to 12wt%-6wt%-12wt% and 12wt%-0wt%-12wt%, the stress and elastic modulus of porous NiTi alloys increased from 228MPa to 321MP and 446MPa, from 4.8GPa to 5.6GPa and 6.8GPa, respectively. Compared with uniform porous materials, gradient porous NiTi alloy exhibited better superelasticity.

Study on Effect of Sintering Temperature on Microstructure and Compressive Property of Porous NiTi Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 480-483 ◽  
Author(s):  
Jing Yuan Yu ◽  
Qiang Li
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Compressive Property ◽  
Powder Metallurgy Method ◽  
Niti Alloys ◽  
Porous Niti ◽  
Universal Testing ◽  
Niti Phase

Porous NiTi alloys were prepared by powder metallurgy method using NH4HCO3as space-holder. The effect of sintering temperature on pore characteristic, phase composition and compressive property of porous NiTi alloys was studied by XRD, SEM, EDS and a universal testing machine. The results show with the increase of sintering temperature the porosity of porous NiTi alloys first increases and then decreases, but the content of NiTi phase, compressive strength and modulous of sintered products continuously increase. When sintered at 980°C for 2h, the porous NiTi alloys have higher porosity of 53.6%, better compressive strength of 173.7MPa and elastic modulous of 4.2GPa. The phases of sinter products are mainly composed by TiNi, Ti2Ni, and TiNi3phases.

The character of the structure formation of model alloys of the Fe-Cr-(Zr, Zr-B) system synthesized by powder metallurgy

2020 ◽  
Vol 2 (100) ◽  
pp. 49-57
Author(s):  
Z.A. Duriagina ◽  
M.R. Romanyshyn ◽  
V.V. Kulyk ◽  
T.M. Kovbasiuk ◽  
A.M. Trostianchyn ◽  
...  
Keyword(s):  
Phase Composition ◽  
Powder Metallurgy ◽  
Chemical Composition ◽  
Structure Formation ◽  
Xrd Analysis ◽  
Model Alloy ◽  
Phase Identification ◽  
Laves Phases ◽  
Cr System ◽  
Sintered Alloys

Purpose: The purpose of the work is to synthesize and investigate the character of structure formation, phase composition and properties of model alloys Fe75Cr25, Fe70Cr25Zr5, and Fe69Cr25Zr5B1. Design/methodology/approach: Model alloys are created using traditional powder metallurgy approaches. The sintering process was carried out in an electric arc furnace with a tungsten cathode in a purified argon atmosphere under a pressure of 6·104 Pa on a water cooled copper anode. Annealing of sintered alloys was carried out at a temperature of 800°C for 3 h in an electrocorundum tube. The XRD analysis was performed on diffractometers DRON-3.0M and DRON-4.0M. Microstructure study and phase identification were performed on a REMMA-102-02 scanning electron microscope. The microhardness was measured on a PMT-3M microhardness meter. Findings: When alloying a model alloy of the Fe-Cr system with zirconium in an amount of up to 5%, it is possible to obtain a microstructure of a composite type consisting of a mechanical mixture of a basic Fe2(Cr) solid solution, solid solutions based on Laves phases and dispersive precipitates of these phases of Fe2Zr and FeCrZr compositions. In alloys of such systems or in coatings formed based on such systems, an increase in hardness and wear resistance and creep resistance at a temperature about 800°C will be reached. Research limitations/implications: The obtained results were verified during laser doping with powder mixtures of appropriate composition on stainless steels of ferrite and ferrite-martensitic classes. Practical implications: The character of the structure formation of model alloys and the determined phase transformations in the Fe-Cr, Fe-Cr-Zr, and Fe-Cr-B-Zr systems can be used to improve the chemical composition of alloying plasters during the formation of ferrite and ferrite-martensitic stainless steel coatings. Originality/value: The model alloys were synthesized and their phase composition and microstructure were studied; also, their microhardness was measured. The influence of the chemical composition of the studied materials on the character of structure formation and their properties was analysed.

Phase composition and wear behavior of NiTi alloys

2008 ◽  
Vol 43 (5) ◽  
pp. 1701-1710 ◽  
Author(s):  
Stefano Gialanella ◽  
Gloria Ischia ◽  
Giovanni Straffelini
Keyword(s):  
Phase Composition ◽  
Wear Behavior ◽  
Niti Alloys

The Influence of Boron Additions in Cast Ti-47AL-2Cr-2Nb-0.8B

1994 ◽  
Vol 364 ◽  
Author(s):  
Daniel S. Schwartz ◽  
Donald S. Shih
Keyword(s):  
Grain Size ◽  
Fine Structure ◽  
Phase Composition ◽  
Titanium Aluminide ◽  
Boron Addition ◽  
Intimate Contact ◽  
Β Phase ◽  
Low Degree ◽  
Degree Of Order ◽  
B2 Structure

AbstractMorphology, fine structure, and chemistry of phases formed in cast Ti-47Al-2Cr-2Nb-0.8B due to boron addition were examined in detail. Boron acts an inoculant, refining and stabilizing the cast grain size. A curving ribbon-shaped phase was present throughout the material, related to the ordered phase Ti2AlCr. The ribbon phase had the B2 structure, with a0∼0.318nm. Many ribbons had a low degree of order, i. e. the material was a BCC mixture of Ti, Al, Nb, and Cr. Ribbon phase composition was variable, measured to be: Ti-(20–30)Al-(2–4)Nb-(5–16)Cr. TiB2 was present in small amounts, always in intimate contact with the ribbon phase. A (100)ribbon ‖ {1100}TiB2, (011)ribbon ‖ {1122}TiB2 orientation relationship was observed. It is proposed that the ribbon phase is a remnant of the high-temperature titanium aluminide β-phase, stabilized by dissolved boron.

Local Graded Structure in 6.5wt%Si-Fe Alloy and the Effect on Ductility

2005 ◽  
Vol 492-493 ◽  
pp. 59-62 ◽  
Author(s):  
Qiang Shen ◽  
Ran Li ◽  
Lian Meng Zhang
Keyword(s):  
Phase Composition ◽  
Powder Metallurgy ◽  
Deformation Behavior ◽  
Powder Metallurgy Method ◽  
Silicon Phase ◽  
Silicon Iron ◽  
Graded Structure ◽  
Composition And Structure ◽  
High Silicon ◽  
Si Content

The changes of phase composition and structure evolvement of Fe and Si powders with the ratio of 6.5wt%Si to 93.5wt%Fe were mainly studied. It is found that, the local graded structure, Fe-Fe(Si)-Fe3Si-(FeSi)-Si, forms due to the obvious diffusion and the alloying reaction between Fe and Si powders when sintering at 900-975oC. The graded structure, in which the high silicon phase based on Fe-Si alloys is packed by the low silicon solution based on Fe, exhibits a graded concentration of Si distribution. And most of the Fe-containing phase remains a state of lower Si content, less than that of 3wt%Si-Fe alloy, thus provides the good deformation behavior of rolling and cutting for the compacts. Therefore, it is feasible for the high silicon iron sheets to be produced by the powder metallurgy method.

scholarly journals Properties Comparison of Ti-Al-Si Alloys Produced by Various Metallurgy Methods

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3084 ◽  
Author(s):  
Anna Knaislová ◽  
Pavel Novák ◽  
Jaromír Kopeček ◽  
Filip Průša
Keyword(s):  
Fracture Toughness ◽  
Phase Composition ◽  
Powder Metallurgy ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Compression Tests ◽  
Large Area ◽  
Fine Grained ◽  
Central Porosity ◽  
Fine Grained Structure

Melting metallurgy is still the most frequently used and simplest method for the processing of metallic materials. Some of the materials (especially intermetallics) are very difficult to prepare by this method due to the high melting points, poor fluidity, or formation of cracks and pores after casting. This article describes the processing of Ti-Al-Si alloys by arc melting, and shows the microstructure, phase composition, hardness, fracture toughness, and compression tests of these alloys. These results are compared with the same alloys prepared by powder metallurgy by the means of a combination of mechanical alloying and spark plasma sintering. Ti-Al-Si alloys processed by melting metallurgy are characterized by a very coarse structure with central porosity. The phase composition is formed by titanium aluminides and titanium silicides, which are full of cracks. Ti-Al-Si alloys processed by the powder metallurgy route have a relatively homogeneous fine-grained structure with higher hardness. However, these alloys are very brittle. On the other hand, the fracture toughness of arc-melted samples is immeasurable using Palmqvist’s method because the crack is stopped by a large area of titanium aluminide matrix.

Preparation of NiCr-Sialon-CaF2 Self-Lubricating Die Material and its Friction at High Temperature

2018 ◽  
Vol 279 ◽  
pp. 167-171
Author(s):  
Hao Yang ◽  
Ming Chang ◽  
Hua Jun Wang ◽  
Zhen Рua Yao
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Friction And Wear ◽  
Material System ◽  
Molding Process ◽  
Vacuum Sintering ◽  
Lubricating Material ◽  
Die Material ◽  
Ratio Of Components

In this study, high-temperature self-lubricating material system (NiCr-Sialon-CaF2) was proposed and samples were prepared by powder metallurgy molding process under proper parameters. Samples with excellent properties can be obtained in a vacuum sintering environment of 1200° C for 2 hours and the ratio of components were Sialon ceramic-5 %, CaF2-10 % and NiCr-the rest. By XRD and EPMA test, the phase composition and its ingredients were examined. And after the high temperature properties analysis of samples with different ingredients, such as surface morphology and friction factor, the high temperature friction and wear mechanism of this self-lubricating material system was illustrated.

Sign in / Sign up

Export Citation Format

Share Document