scholarly journals A review of recent developments in Fe3Al-based alloys

1991 ◽  
Vol 6 (8) ◽  
pp. 1779-1805 ◽  
Author(s):  
C.G. McKamey ◽  
J.H. DeVan ◽  
P.F. Tortorelli ◽  
V.K. Sikka
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Iron Aluminides ◽  
Alloy Development ◽  
Sharp Drop ◽  
Environmental Embrittlement ◽  
Room Temperature Ductility ◽  
Structural Applications ◽  
Recent Developments ◽  
Mechanical Properties And Corrosion

Fe3Al-based iron aluminides have been of interest for many years because of their excellent oxidation and sulfidation resistance. However, limited room temperature ductility (<5%) and a sharp drop in strength above 600 °C have limited their consideration for use as structural materials. Recent improvements in tensile properties, especially improvements in ductility produced through control of composition and microstructure, and advances in the understanding of environmental embrittlement in intermetallics, including iron aluminides, have resulted in renewed interest in this system for structural applications. The purpose of this paper is to summarize recent developments concerning Fe3Al-based aluminides, including alloy development efforts and environmental embrittlement studies. This report will concentrate on literature published since about 1980, and will review studies of fabrication, mechanical properties, and corrosion resistance that have been conducted since that time.

Mechanical properties of nickel beryllides

1989 ◽  
Vol 4 (6) ◽  
pp. 1347-1353 ◽  
Author(s):  
T. G. Nieh ◽  
J. Wadsworth ◽  
C. T. Liu
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Elastic Properties ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Interstitial Oxygen ◽  
Equiatomic Composition ◽  
Room Temperature Ductility ◽  
Hardness Increase ◽  
Microhardness Tester

The elastic properties of nickel beryllide have been evaluated from room temperature to 1000 °C. The room temperature modulus is measured to be 186 GPa, which is relatively low by comparison with other B2 aluminides such as NiAl and CoAl. Hardness measurements were carried out on specimens that had compositions over the range from 49 to 54 at. % Be, using both a Vickers microhardness tester and a nanoindentor. It was found that the hardness of NiBe exhibits a minimum at the equiatomic composition. This behavior is similar to that of aluminides of the same crystal structure, e.g., NiAl and CoAl. The effect of interstitial oxygen on the hardness of NiBe has also been studied and the results show that the presence of oxygen in NiBe can cause a significant increase in hardness. It is demonstrated that the hardness increase for the off-stoichiometric compositions is primarily caused by interstitial oxygen and can only be attributed partially to anti-site defects generated in off-stoichiometric compositions. Nickel beryllides appear to have some intrinsic room temperature ductility, as evidenced by the absence of cracking near hardness indentations.

Modification in Texture of Magnesium by the Addition of Rare Earth Elements and its Influence on Mechanical Properties

2012 ◽  
Vol 736 ◽  
pp. 307-315 ◽  
Author(s):  
Murugavel Suresh ◽  
Satyam Suwas
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Magnesium Alloys ◽  
Aluminium Alloys ◽  
Room Temperature ◽  
Main Obstacle ◽  
Rare Earth Addition ◽  
Structural Applications ◽  
Re Elements ◽  
The Relationship

Mg alloys show limited room temperature formability compared to its lightweight counterpart aluminium alloys, which is a main obstacle in using this metal for most of the structural applications. However, it is known that grain refinement and texture control are the two possibilities for the improvement of formability of magnesium alloys. Amongst the approaches attempted for the texture weakening, additions through of rare-earth (RE) elements have been found most effective. The relationship between the texture and ductility is well established. In this paper, the effect of rare earth addition on texture weakening has been summarized for various magnesium alloys under the two most common modes of deformation methods.

Effect of Aging Process on Microstructure and Room Temperature Ductility of TB6 Titanium Alloy

2014 ◽  
Vol 1061-1062 ◽  
pp. 567-570
Author(s):  
Cui Ye ◽  
Fei Zhao ◽  
Fang Zhou ◽  
Ni Li ◽  
Jun Shuai Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Aging Time ◽  
Aging Temperature ◽  
Aging Process ◽  
Room Temperature ◽  
Room Temperature Ductility ◽  
Tb6 Titanium Alloy

Microstructure and room temperature ductility of the TB6 titanium alloy was investigated by varying the aging temperature and the aging time.The results show that, the alloy’s contraction of area increases while the tensile strength firstly increases and then decreases by raising their aging temperature. In general, the ductility of the samples increases and the strength decreases with the increasing aging time. The optimum mechanical properties are obtained by aging at 650 °C for 2 h.

Phase Stability, Microstructure and Mechanical Properties in the Multi-Phse Alloys Based on the L12-Ni3(Al,Be)

1994 ◽  
Vol 364 ◽  
Author(s):  
Takahiro Matsuo ◽  
Hideki Hosoda ◽  
Seiji Miura ◽  
Yoshinao Mishima
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Room Temperature ◽  
Vertical Section ◽  
Intermetallic Alloys ◽  
Primary Solidification Phase ◽  
Four Point Bending ◽  
Room Temperature Ductility ◽  
Three Phase ◽  
Multi Phase

AbstractIntermetallic alloys based on the Ll2 Ni3(Al,Be) phase in the ternary Ni-Al-Bc system are prepared so that the alloys are multi-phase with the B2 intermetallic compound NiBe and a Ni primary solid solution denoted as (Ni). Such three-phase alloys, Ni-16 to 20 at%Al-10 at%Be, exhibit good room temperature ductility as measured by four-point bending. In order to examine the phase stabilities and relations among constituent phases, a vertical section of the ternary system is constructed at a constant 10 at%Bc mainly by differential thermal analysis. It is found that improvement in room temperature ductility can be achieved by the formation of a fine mixture of constituent phases during invariant reactions during solidification, which is further enhanced by the co-existence of the Ll2 phase formed as the primary solidification phase.

Shape Memory Behavior and Mechanical Properties of NiMn and Ni(Mn,X) Alloys

1991 ◽  
Vol 246 ◽  
Author(s):  
W.S. Yang ◽  
D.E. Mikkola
Keyword(s):  
Mechanical Properties ◽  
Transition Temperature ◽  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Transformation Temperatures ◽  
Room Temperature Ductility ◽  
Substitutional Solute ◽  
Ternary Element ◽  
High Transition

AbstractPotential high transition temperature shape memory alloys based on NiMn have been studied with emphasis on the shape recovery, transformation temperatures and mechanical properties. Binary NiMn, which has been reported to be brittle, has a low shape recovery, but this can be increased with Al or Ti additions. Also, the transformation temperature can be changed and the room temperature ductility improved by ternary element additions. The various substitutional solute characteristics affecting the shape recovery, the transformation temperatures, and the ductility have been examined.

Microstructure Evolution and Mechanical Properties of Extruded Mg-Al-Zn-Sn Alloy Sheets

2017 ◽  
Vol 898 ◽  
pp. 300-304
Author(s):  
Qing Shan Yang ◽  
Wen Jun Liu ◽  
Zu Jian Yu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Mg Alloy ◽  
Casting Method ◽  
Mechanical Responses ◽  
Room Temperature Ductility ◽  
Differential Speed ◽  
Scanning Electron

The microstructure and mechanical responses of the AZ31 with the addition of 1.8% Sn alloys have been studied and compared. Mg alloy sheets were prepared with metal model casting method and subsequent processes by conventional extrusion (CE) and differential speed extrusion (DSE). Mg alloys were hot extruded at 400oC with the extrusion ratio of 101:1. The microstructure of Mg alloy sheets was examined by optical microscopy (OM) and scanning electron microscope (SEM). The results indicated that the grains were dynamically recrystallized after the extrusion process. Moreover, DSE process dramatically enhanced the room temperature ductility of the extruded sheets. It was also presented that the Mg alloy processed by DSE exhibite a classical dimple structure as a result of slip accumulation and ductile tear.

Effect of hafnium addition on a Ni-Al-Co Alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 940-941
Author(s):  
L. S. Lin ◽  
G. W. Levan ◽  
S. M. Russell ◽  
C. C. Law
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Ternary Alloy ◽  
Room Temperature ◽  
Gamma Prime ◽  
Room Temperature Ductility ◽  
Appreciable Increase ◽  
Hf Addition

Recent efforts at P&W have shown that the addition of cobalt to binary NiAl results in an appreciable increase in room temperature ductility. One version of this ternary alloy, designated VIM A, has a composition of Ni-30 at.% Al-35 at.% Co. The addition of 0.5 at.% Hf to this alloy (designated VIM AH) results in an improvement in yield strength at 760°C. Room temperature properties were not found to be significantly affected by the Hf addition. This discussion will focus on the microstructures of alloys VIM A and VIM AH and their relationship to the mechanical properties observed in compression at room temperature and 760°C.The addition of hafnium reduced the grain size of VIM AH alloy. After room temperature compression, both alloys show an ordered bcc (B2) matrix and precipitates which are distributed primarily along grain boundaries. These precipitates were identified by microdiffraction to be ordered fcc (L12) gamma prime for VIM A and hexagonal (A3) for VIM AH.

Microstructures and Mechanical Properties of NiAl+Mo In-Situ Eutectic Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
P. R. Subramanian ◽  
M. G. Mendiratta ◽  
D. B. Miracle ◽  
D. M. Dimiduk
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Room Temperature ◽  
Composite System ◽  
Elevated Temperatures ◽  
Two Phase ◽  
Structural Applications ◽  
Temperature Fracture

AbstractThe quasibinary NiAI-Mo system exhibits a large two-phase field between NiAl and the terminal (Mo) solid solution, and offers the potential for producing in-situ eutectic composites for high-temperature structural applications. The phase stability of this composite system was experimentally evaluated, following long-term exposures at elevated temperatures. Bend strengths as a function of temperature and room-temperature fracture toughness data are presented for selected NiA1-Mo alloys, together with results from fractography observations.

The Influence of Microstructure, Heat-Treatment and Type of Crystal Lattice of Iron Aluminides on Coefficient of Thermal Expansion

2016 ◽  
Vol 368 ◽  
pp. 41-44 ◽  
Author(s):  
Martin Švec
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Thermal Expansion ◽  
High Temperature ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Iron Aluminides ◽  
Sharp Drop ◽  
Structural Application ◽  
Phase Transition Temperatures

The iron aluminides seem to be very perspective materials for high temperature structural application. They have many advantages, but unfortunately also some negative properties – e.g. sharp drop in strength above 600°C or limited ductility at room temperature. These disadvantages can be reduced by alloying of binary alloy by other elements.Present work deals with a study of coefficient of thermal expansion (CTE). It was investigated the influence of microstructure and heat-treatment on the values of CTE. Secondary, it was studied the possibilities, how to determine phase transition temperatures from CTE curves. Influence of type of iron aluminides lattice on CTE values was also examined as well as the influence of addition of alloying elements into binary iron aluminides.

Sign in / Sign up

Export Citation Format

Share Document