Powder Processing of NiAl for Elevated Temperature Strength

1996 ◽  
Vol 460 ◽  
Author(s):  
J. Daniel Whittenberger ◽  
Peter Grahle ◽  
Eduard Arzt ◽  
Robert Behr ◽  
Klaus Zöltzer ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Grain Boundaries ◽  
Powder Processing ◽  
Hot Extrusion ◽  
Oxide Dispersion Strengthened ◽  
Gaseous Nitrogen ◽  
Elevated Temperature Strength ◽  
Alternative Means ◽  
Nial Powder ◽  
Nial Matrix

ABSTRACTIn an effort to superimpose two different elevated temperature strengthening mechanisms in NiAl, one lot of an oxide dispersion strengthened (ODS) NiAl powder has been milled in liquid nitrogen (cryomilled) to introduce A1N particles at the grain boundaries, and a second lot of ODS powder was simply roasted in gaseous nitrogen as an alternative means to produce AIN reinforced grain boundaries. Powder from both of these lots as well as the starting material have been consolidated by hot extrusion and tested at 1300 K. Both nitrogen roasting and cryomilling produced AIN within the ODS NiAl matrix which strengthened the alloy; however, based on the AIN content, cryomilling is more effective.

Elevated temperature compressive properties of reaction milled NiAl–AlN and Zr-doped NiAl–AlN composites

1992 ◽  
Vol 7 (10) ◽  
pp. 2724-2732 ◽  
Author(s):  
J. Daniel Whittenberger ◽  
Michael J. Luton
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
High Intensity ◽  
Creep Resistance ◽  
High Strength ◽  
Milling Process ◽  
Compressive Properties ◽  
Reaction Milling ◽  
Nial Powder ◽  
Nial Matrix

Previous studies of a single lot of NiAl powder which had been ground under high intensity conditions in liquid nitrogen (cryomilling) indicated that this processing leads to a high strength, elevated temperature NiAl–AlN composite. Because this was the first known example of the use of the reaction milling process to produce a high temperature composite, the reproducibility of this technique was unknown. Two additional lots of NiAl powder and a lot of a Zr-doped NiAl powder have been cryomilled, and analyses indicate that AlN was formed within a NiAl matrix in all three cases. Compression testing between 1200 K and 1400 K has shown that the deformation resistance of these heats is similar to that of the first lot of NiAl–AlN; thus cryomilling can improve the creep resistance of NiAl by a factor of six. Based on this work, it is concluded that cryomilling of NiAl powder to form high temperature, high strength NiAl–AlN composites is a reproducible process.

scholarly journals Development of Hot-Extruded Mg–RE–Zn Alloy Bar with High Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1722 ◽  
Author(s):  
Zehua Li ◽  
Jinghuai Zhang ◽  
Yan Feng ◽  
Jinshu Xie ◽  
Yinfu Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Elevated Temperature ◽  
Basal Plane ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Hot Extrusion ◽  
Tensile Yield Strength ◽  
Elevated Temperature Strength ◽  
Solid Solution Treatment

A new elevated-temperature high-strength Mg–4Er–2Y–3Zn–0.4Mn (wt %) alloy was developed by semi-continuous casting, solid solution treatment, and hot extrusion. W phase (Mg3(Er,Y)2Zn3) with fcc structure, long period stacking ordered phases with 18R (Mg10(Er,Y)1Zn1) and 14H (Mg12(Er,Y)1Zn1) structures, and basal plane stacking faults (SFs) was formed in the as-cast alloy, mainly due to the alloy component of (Er + Y)/Zn = 1:1 and Er/Y = 1:1 (at %). After solid solution treatment and hot extrusion, the novel microstructure feature formed in as-extruded alloy is the high number-density nanospaced basal plane SFs throughout all the dynamically recrystallized (DRXed) and un-DRXed grains, which has not been previously reported. The as-extruded alloy exhibits superior tensile properties from room temperature to 300 °C. The tensile yield strength can be maintained above 250 MPa at 300 °C. The excellent elevated-temperature strength is mainly ascribed to the formation of nanospaced basal plane SFs throughout the whole Mg matrix, fine DRXed grains ~2 μm in size, and strongly basal-textured un-DRXed grains with profuse substructures. The results provide new opportunities for the development of deformed Mg alloys with satisfactory mechanical properties for high-temperature services.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Characterization of oxide particles in ODS austenitic stainless steel after heavy ion irradiation up to high doses

2011 ◽  
Vol 1298 ◽  
Author(s):  
Hiroshi Oka ◽  
Yosuke Yamazaki ◽  
Hiroshi Kinoshita ◽  
Naoyuki Hashimoto ◽  
Somei Ohnuki ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ion Irradiation ◽  
Hot Extrusion ◽  
Oxide Dispersion Strengthened ◽  
Complex Oxide ◽  
Heavy Ion ◽  
Oxide Particles ◽  
The Difference ◽  
High Doses

ABSTRACTOxide dispersion strengthened austenitic stainless steel (ODS316), which is based on advanced SUS316 steel, has been developed by mechanically alloying and hot extrusion. Hafnium and titanium were added to make a fine distribution of oxide particles. The stability of oxide particles dispersed in ODS316 under irradiation was evaluated after 250 keV Fe+ irradiation up to high doses at 500 °C. TEM observation and EDS analysis indicated that fine complex oxide particles with Y, Hf and Ti were mainly dispersed in the matrix. There are no significant changes in the distribution and the size of oxide particles after irradiation. It was also revealed that the constitution ratio of Ti in complex oxide appeared to be decreased after irradiation. This diffuse-out of Ti during irradiation could be explained by the difference in oxide formation energy among alloying elements.

scholarly journals Enhancing elevated temperature strength of copper containing aluminium alloys by forming L12 Al3Zr precipitates and nucleating θ″ precipitates on them

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Surendra Kumar Makineni ◽  
Sandeep Sugathan ◽  
Subhashish Meher ◽  
Rajarshi Banerjee ◽  
Saswata Bhattacharya ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Aluminium Alloys ◽  
Elevated Temperature Strength

The Effect of Low-Angle and High-Angle Grain Boundaries on Elevated Temperature Strength

1994 ◽  
Vol 362 ◽  
Author(s):  
M. E. Kassner
Keyword(s):  
Elevated Temperature ◽  
Mechanical Behavior ◽  
Large Angle ◽  
High Angle ◽  
Elevated Temperature Strength ◽  
Ambient Temperatures ◽  
The Past ◽  
Creep Regime ◽  
New Evidence ◽  
General Opinion

AbstractThe influence of small (subgrain) misorientation interfaces on the mechanical behavior of metals and alloys deforming within the creep regime has been intensively studied over the past several decades. Controversies have existed, but some new experiments suggest, contrary to the general opinion, that low-angle boundaries are not associated with the rate controlling process for plasticity and do not affect strength. The new evidence will be discussed in terms of other established experimental trends. Large-angle boundaries may have a smaller effect on elevated temperature strength than at ambient temperatures and do not appear to dramatically affect elevated temperature strength. Superplastic effects are not addressed.

scholarly journals Alloying effects of Ag on grain boundaries and alumina interfaces in copper: a first principles prediction

RSC Advances ◽  
2017 ◽  
Vol 7 (76) ◽  
pp. 48230-48237 ◽  
Author(s):  
F. Teng ◽  
G. Q. Lan ◽  
Y. Jiang ◽  
M. Song ◽  
S. J. Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
First Principles ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Oxide Interfaces ◽  
Alloying Effects

The mechanical properties of oxide dispersion-strengthened copper are largely dictated by its internal interfaces, i.e. the oxide interfaces and the grain boundaries (GBs).

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