IN792 DS Superalloy: Optimization of EB Welding and Post-Welding Heat Treatments

2016 ◽  
Vol 879 ◽  
pp. 175-180 ◽  
Author(s):  
Giuseppe Barbieri ◽  
Peiman Soltani ◽  
Saulius Kaciulis ◽  
Roberto Montanari ◽  
Alessandra Varone
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Beam Current ◽  
Heat Treatments ◽  
The Other ◽  
Process Conditions ◽  
Eb Welding ◽  
Directionally Solidified ◽  
Thick Plates ◽  
Acceleration Voltage

Electron beam (EB) welding has been used to realize the seams on 2 mm thick plates of directionally solidified (DS) IN792 superalloy. A grid of the samples has been prepared by varying the pass speed v from 1 to 2.5 m/min, while the other process parameters (power P = 1 kW, acceleration voltage T = 50 kV, beam current I = 20 mA) were kept constant. Experiments were carried out both at room temperature and with pre-heating at 200 °C or 300 °C.Once found the best process conditions (pre-heating at 300 °C; v = 2.5 m/min) the effect of post-welding heat treatments at 700 and 750 °C for increasing time up to 2 hours has been investigated.

Welding of IN792 DS Superalloy by High Energy Density Techniques

2017 ◽  
Vol 884 ◽  
pp. 166-177 ◽  
Author(s):  
Giuliano Angella ◽  
Giuseppe Barbieri ◽  
Riccardo Donnini ◽  
Roberto Montanari ◽  
Alessandra Varone
Keyword(s):  
Electron Beam ◽  
Energy Density ◽  
Room Temperature ◽  
High Energy ◽  
The Other ◽  
High Energy Density ◽  
Process Conditions ◽  
Directionally Solidified ◽  
Thick Plates ◽  
Welding Technique

Laser (LBW) and Electron Beam (EBW) welding have been used to produce seams on 2 mm thick plates of directionally solidified (DS) IN792 superalloy. For each welding technique a grid of samples were prepared by varying the pass speed (v) and keeping constant the other process parameters. The experiments were carried out at room temperature and with pre-heating (PHT) at 200 °C and 300 °C to find the best process conditions. The microstructural changes in molten zone (MZ) and heat affected zone (HAZ) were investigated finding that EBW guarantee a better quality and efficiency of the process without any macro defects. About the microstructure, the amount of ordered γ’ phase in the MZ is similar (≈ 25 %) for both welding techniques and quite lower than the value (70 %) of the original alloy.

Electron Beam Welding of Ti-24Al-17Nb-0.5Mo Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 821-824
Author(s):  
J.Y. Zou ◽  
Yu You Cui ◽  
Rui Yang
Keyword(s):  
Electron Beam ◽  
Base Metal ◽  
Room Temperature ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Weld Zone ◽  
Welding Parameters ◽  
Eb Welding ◽  
Phase Combination ◽  
Postweld Heat

Electron beam (EB) welding of Ti-24Al-17Nb-0.5Mo (at.%) alloy and the effects of postweld heat treatments (PWHT) were studied. Through optimizing the welding parameters, defect-free welding joint was obtained. For the as-welded joint, the fusion zone (FZ) consisted of predominant β and occasional α2 within β grains. Microhardness of FZ was higher than that of the base metal (BM) and that of the heat affected zone (HAZ) was between that of BM and FZ. PWHTs greatly modified the microstructures and mechanical properties of the weld zone. PWHTs at both 820oC and 900oC yielded fine acicular laths in FZ leading to severe brittleness of the weld. Appropriate microstructures and phase combination were obtained by PWHT at 1000oC for 2 h, and room-temperature tensile strength reached the value of the base metal after the same thermal cycle.

Microstructure and Mechanical Properties of an Advanced Niobium Based Ultrahigh Temperature Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3690-3695 ◽  
Author(s):  
X.P. Guo ◽  
L.M. Gao ◽  
Ping Guan ◽  
K. Kusabiraki ◽  
Heng Zhi Fu
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Directional Solidification ◽  
Room Temperature ◽  
Zone Melting ◽  
Floating Zone ◽  
Directionally Solidified ◽  
Microstructure And Mechanical Properties ◽  
Temperature Fracture ◽  
Ultrahigh Temperature

The microstructure and mechanical properties including room temperature fracture toughness Kq, tensile strengthσb and elongationδ at 1250°C of the Nb based alloy directionally solidified in an electron beam floating zone melting (EBFZM) furnace have been evaluated. The microstructure is primarily composed of Nb solid solution (Nbss), α-(Nb)5Si3 and (Nb)3Si phases. After directional solidification with the moving rate of electron beam gun R being respectively 2.4, 4.8 and 7.2 mm/min, the primary Nbss dendrites, Nbss + (Nb)5Si3/(Nb)3Si eutectic colonies (lamellar or rod-like) and divorced Nb silicide plates align along the longitudinal axes of the specimens. When R = 2.4 mm/min, the best directional microstructure is obtained. Directional solidification has significantly improved theσb at 1250°C and Kq. The maximumσb occurs for the specimens with R = 2.4 mm/min and is about 85.0 MPa, meanwhile, the Kq is about 19.4 MPam1/2.

Low Acceleration Voltage EBIC Using FESEM and Application to Cross-Sectional Junction Evaluation

1996 ◽  
Author(s):  
Y. Kadota ◽  
K. Mori
Keyword(s):  
Electron Beam ◽  
Current Method ◽  
Beam Current ◽  
Primary Electron ◽  
Electron Beam Current ◽  
Junction Depth ◽  
Primary Electron Beam ◽  
Cross Sectional ◽  
Electron Beam Induced Current ◽  
Acceleration Voltage

Abstract EBIC (Electron beam induced current) method has been applied to the evaluation of half micron MOSFET junctions. We have been able to clearly measure the junction depth profile and the impurities density, using FESEM/EBIC which provides the highest SEM resolution currently available. We have found that it is necessary to understand the relation of the acceleration voltage and the primary electron beam current, in order to take full advantage of the FESEM/EBIC technique for junction evaluation. We have been able to experimentally demonstrate the accurate measurement of junction position.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

High energy resolution spectrometer for the dedicated STEM

1984 ◽  
Vol 42 ◽  
pp. 558-559 ◽  
Author(s):  
P.E. Batson
Keyword(s):  
Collection Efficiency ◽  
Core Loss ◽  
Beam Current ◽  
High Energy ◽  
High Energy Resolution ◽  
Acquisition Time ◽  
Good Definition ◽  
Loss Analysis ◽  
Definition Of ◽  
Acceleration Voltage

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

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