Structural changes occurring during thermomechanical treatment of steel and their influence on the mechanical properties

1966 ◽  
Vol 7 (11) ◽  
pp. 709-717 ◽  
Author(s):  
A. P. Gulyaev
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Treatment ◽  
Structural Changes

Influence of Severe Thermomechanical Treatment on Formation of Nanocrystalline Structure in Ni 718 and Ni 718Plus Alloys and their Mechanical Properties

2008 ◽  
Vol 584-586 ◽  
pp. 458-463 ◽  
Author(s):  
Shamil Kh. Mukhtarov ◽  
Vener Valitov ◽  
M.F.X. Gigliotti ◽  
P.R. Subramanian ◽  
J.S. Marte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Treatment ◽  
Structural Changes ◽  
Nanocrystalline Structure ◽  
Grain Structure ◽  
Total Strain ◽  
Recrystallization Temperature ◽  
Uniform Structure ◽  
Processing Temperature ◽  
Alloy 718

The influence of severe thermomechanical treatment via multiple forging on the formation of a nanocrystalline (NC) structure in bulk samples of Alloy 718 and ATI 718Plus has been investigated. It was observed that a step-wise decrease of processing temperature from 950 down to 575°C allowed the refinement of the initial coarse grain structure to a NC state. Investigations of structural changes in the deformed samples have shown that extending the temperature interval of dynamic recrystallization to low homologous temperatures resulted in the formation of a fine-grained recrystallized structure. The temperature of NC structure formation in ATI Alloy 718Plus was 50-100°С higher than that required for alloy 718. This was due to the presence of the additional γ′-phase, which increased the recrystallization temperature. This decreased the total strain required to produce NC structure, as compared with Alloy 718. It was observed that increasing the total strain and decreasing temperatures step-wise during deformation via multiple forging resulted in a uniform structure across the cross-section of the samples. The room temperature mechanical properties of the investigated alloys with various grain sizes are also compared.

scholarly journals Correlation between mechanical properties and structural changes of the sintered Cu-4 at% Ag alloy during thermomechanical treatment

2008 ◽  
Vol 62 (2) ◽  
pp. 78-84
Author(s):  
Ivana Rangelov ◽  
Svetlana Nestorovic ◽  
Desimir Markovic
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Thermomechanical Treatment ◽  
Structural Changes ◽  
Solute Segregation ◽  
Recrystallization Temperature ◽  
Micro Structure ◽  
Deformation Degree ◽  
Sintered Copper ◽  
Anneal Hardening

Influence of thermomechanical treatment on micro structure and strength (hardness and microhardness) of the sintered copper based Cu-4 at% Ag alloy was investigated using Vickers hardness and microhardness measurements, and optical microscopy. After sintering at 790?C, samples of Cu-4 at% Ag alloy were subjected to thermomechanical treatment by cold rolling with 20, 40 and 60% deformation degrees, and annealing below and over the recrystallization temperature. It was shown that microstructure of Cu-4 at% Ag alloy changed with thermomechanical treatment, which directly causes changes of mechanical properties. Optical microphotograph of the sintered Cu-4 at% Ag alloy shows relatively homogeneous structure with spherical pores presented. The strength (hardness and microhardness) of the sintered Cu-4 at% Ag alloy during cold rolling increases with deformation degree due to deformation strengthening. Maximum values of hardness and microhardness were for 60% deformation. The porosity still exists in spite of the fact that compacting was carried out during the cold rolling. The hardness and microhardness continue to increase after annealing at temperature bellow recrystallization temperature due to anneal hardening effect which occurs in a temperature range of 160-350?C. It was concluded that solute segregation to dislocations, analogous to the formation of Cottrel atmosphere in interstitial solid solutions, is primarily responsible for anneal hardening phenomenon. Annealing at higher temperatures (higher than 400?C) results in strength decrease due to beginning of alloy recrystallization.

Changes of Selected Structural and Mechanical Properties of the Strzelin Granites As Induced By Thermal Loads / Wpływ Obciążeń Termicznych Na Zmiany Niektórych Strukturalnych I Mechanicznych Właściwości Granitów Strzelińskich

2012 ◽  
Vol 57 (4) ◽  
pp. 951-974 ◽  
Author(s):  
Andrzej Nowakowski ◽  
Mariusz Młynarczuk
Keyword(s):  
Mechanical Properties ◽  
Nuclear Waste ◽  
Structural Changes ◽  
Structural Parameters ◽  
Total Porosity ◽  
Fracture Network ◽  
Qualitative Description ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Waste Repositories

Abstract Temperature is one of the basic factors influencing physical and structural properties of rocks. A quantitative and qualitative description of this influence becomes essential in underground construction and, in particular, in the construction of various underground storage facilities, including nuclear waste repositories. The present paper discusses the effects of temperature changes on selected mechanical and structural parameters of the Strzelin granites. Its authors focused on analyzing the changes of granite properties that accompany rapid temperature changes, for temperatures lower than 573ºC, which is the value at which the β - α phase transition in quartz occurs. Some of the criteria for selecting the temperature range were the results of measurements carried out at nuclear waste repositories. It was demonstrated that, as a result of the adopted procedure of heating and cooling of samples, the examined rock starts to reveal measurable structural changes, which, in turn, induces vital changes of its selected mechanical properties. In particular, it was shown that one of the quantities describing the structure of the rock - namely, the fracture network - grew significantly. As a consequence, vital changes could be observed in the following physical quantities characterizing the rock: primary wave velocity (vp), permeability coefficient (k), total porosity (n) and fracture porosity (η), limit of compressive strength (Rσ1) and the accompanying deformation (Rε1), Young’s modulus (E), and Poisson’s ratio (ν).

Effect of micro-structural changes on mechanical properties of La66Al14(Cu, Ni)20 amorphous and crystalline alloys

2004 ◽  
Vol 12 (10-11) ◽  
pp. 1279-1283 ◽  
Author(s):  
Y. Zhang ◽  
M.L. Lee ◽  
H. Tan ◽  
Q. Jing ◽  
Y. Li
Keyword(s):  
Mechanical Properties ◽  
Structural Changes

Sintered High Carbon Steels: Effect of Thermomechanical Treatments on their Mechanical and Wear Performance

2008 ◽  
Vol 591-593 ◽  
pp. 271-276 ◽  
Author(s):  
M.A. Martinez ◽  
R. Calabrés ◽  
J. Abenojar ◽  
Francisco Velasco
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Powder Metallurgy ◽  
Thermomechanical Treatment ◽  
Bending Strength ◽  
Carbon Steels ◽  
Tool Steels ◽  
High Carbon ◽  
Wear Performance ◽  
Metallographic Study

In this work, ultrahigh carbon steels (UHCS) obtained by powder metallurgy with CIP and argon sintered at 1150°C. Then, they were rolled at 850 °C with a reduction of 40 %. Finally, steels were quenched at 850 and 1000 °C in oil. In each step, hardness, bending strength and wear performance were evaluated. Obtained results are justified with a metallographic study by SEM. Both mechanical properties and wear resistance are highly favoured with the thermomechanical treatment that removes the porosity of the material. Moreover, final quenching highly hardens the material. The obtained material could be used as matrix for tool steels.

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