AEM Investigation of a Thermomechanically Processed U-6NB Alloy

1985 ◽  
Vol 43 ◽  
pp. 354-355
Author(s):  
Gail M. Ludtka
Keyword(s):  
Mechanical Properties ◽  
Solution Heat Treatment ◽  
Room Temperature ◽  
Thermomechanical Processing ◽  
High Yield ◽  
Ultrafine Grain ◽  
Superplastic Behavior ◽  
High Yield Strength ◽  
Ultrafine Grain Size ◽  
Before And After

The uranium-6 niobium (U-6Nb) alloy has been shown to exhibit elongations of 400-600% after a thermomechanical processing (TMP) sequence. This sequence (below the monotectoid temperature of 647°C) was utilized to develop the ultrafine grain size essential for superplastic behavior. The room temperature mechanical properties of the thermomechanically processed (TMP) U- 6Nb alloy before and after a gamma solution heat treatment (GSHT) were measured and compared to conventionally processed, GSHT U-6Nb alloy. These data are in Table I. The data show that the GSHT conditions have comparable mechanical properties and, so, the prior TMP treatment does not cause any loss of properties. However, the as-thermomechanically processed U-6Nb alloy exhibits negligible ductility and an extremely high yield strength. Metallography and AEM techniques have been utilized to characterize the TMP U- 6Nb microstructure to explain this behavior.

The Effect of Process Route on the Mechanical Properties and Microstructure Aluminum Al-Si-Cu-Mg-Mn Alloys

2020 ◽  
Vol 402 ◽  
pp. 67-72
Author(s):  
Rahmawaty ◽  
Surya Dharma ◽  
Abdul Razak ◽  
Sarjianto ◽  
Nisfan Bahri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Solution Treatment ◽  
Hardness Test ◽  
Optical Microscope ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Process Route ◽  
Ultrafine Grain Size

Equal-channel angular pressing (ECAP) is an effective fabrication process to modify ultrafine grain size. It is believed that the smaller grain size could improve the mechanical properties. In the present work, the solution treatment applied to Al-Si-Cu-Mg-Mn alloy. Furthermore, two models of ECAP have been done through one-to-three pass at room temperature. The microstructures were observed by optical microscope (OM) and scanning electron microscope (SEM). The micro-hardness of longitudinal plane was analyzed by vickers hardness test. The strength of ECAP materials at room temperature was obtained by using tensile test. The results show that the ECAP process has improved mechanical properties of alloys, which were the hardness and ultimate tensile strength tend to increase since single pass stage.

Microstructure and Mechanical Properties of Nanostructured Intermetallic Alloy Based on Ti2AlNb

2008 ◽  
Vol 584-586 ◽  
pp. 153-158
Author(s):  
M.R. Shagiev ◽  
G.A. Salishchev
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Room Temperature ◽  
Thermomechanical Processing ◽  
Nanocrystalline Structure ◽  
Nanostructured Material ◽  
Intermetallic Alloy ◽  
Superplastic Behavior ◽  
Average Grain Size ◽  
Rolling Temperatures

Homogeneous nanocrystalline structure with the average grain size of about 300 nm was produced in Ti2AlNb-based intermetallic alloy by a thermomechanical processing which included multistep isothermal forging at temperatures below the β-transus and intermediate annealings. Nanostructured material possessed excellent mechanical properties. At room temperature, elongations up to 25% were obtained and the ultimate strength reached 1400 MPa. The alloy exhibited superplastic behavior in the temperature range of 850-1000°C. The maximum elongation of 930% and steady state flow stress σ50 of about 125 MPa were obtained at 900°C and strain rate of 4.2×10-3 s-1. The rolling temperatures of nanostructured alloy were defined from analysis of its mechanical behavior at a typical rolling strain rate of about 10-1 s-1 and intermetallic sheets with improved mechanical properties were produced.

DEVELOPMENT OF HIGH STRENGTH Mg-Cu-Zn ULTRAFINE EUTECTIC COMPOSITES WITH ENHANCED PLASTICITY

2009 ◽  
Vol 23 (06n07) ◽  
pp. 947-952 ◽  
Author(s):  
KIAN SONG ◽  
KI BUEM KIM ◽  
JIN MAN PARK ◽  
JAE SEOL LEE ◽  
JOON SIK PARK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Strain ◽  
Yield Strength ◽  
Room Temperature ◽  
High Strength ◽  
Eutectic Structure ◽  
High Yield ◽  
Length Scale ◽  
High Yield Strength ◽  
Micrometer Size

Mg - Cu - Zn ultrafine eutectic composites with different length scale heterogeneity, consisting of micrometer size dendrites and/or ultrafine scale bimodal eutectics, exhibit high yield strength as well as good plasticity at room temperature compression. Among these alloys, micron-scale α- Mg dendrites reinforced ultrafine eutectic composites exhibit high yield strength of 310 ~ 420 MPa and large plasticity of 7 ~ 12%. Meanwhile, a Mg 72Cu5Zn23 alloy comprising a bimodal eutectic structure without the micron-scale α- Mg dendrites shows the optimized mechanical properties the highest yield strength of 455 MPa combined with a considerable plastic strain of ~5%.

scholarly journals Microstructure and mechanical properties of slowly cooled Cu47.5Zr47.5Al5

2007 ◽  
Vol 22 (2) ◽  
pp. 326-333 ◽  
Author(s):  
J. Das ◽  
S. Pauly ◽  
C. Duhamel ◽  
B.C. Wei ◽  
J. Eckert
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Volume Fraction ◽  
Spherical Shape ◽  
High Yield ◽  
High Yield Strength ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Martensite Matrix

Cu47.5Zr47.5Al5 was prepared by arc melting and solidified in situ by suction casting into 2–5-mm-diameter rods under various cooling rates (200–2000 K/s). The microstructure was investigated along the length of the rods by electron microscopy, differential scanning calorimetry and mechanical properties were investigated under compression. The microstructure of differently prepared specimens consists of macroscopic spherical shape chemically inhomogeneous regions together with a low volume fraction of randomly distributed CuZr B2 phase embedded in a 2–7 nm size clustered “glassy-martensite” matrix. The as-cast specimens show high yield strength (1721 MPa), pronounced work-hardening behavior up to 2116 MPa and large fracture strain up to 12.1–15.1%. The fracture strain decreases with increasing casting diameter. The presence of chemical inhomogenities and nanoscale “glassy-martensite” features are beneficial for improving the inherent ductility of the metallic glass.

scholarly journals Is Superplasticity in the Future of Nanophase Materials?

1990 ◽  
Vol 196 ◽  
Author(s):  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Atomic Clusters ◽  
Diffusional Creep ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Nanophase Materials ◽  
Boundary Sliding

ABSTRACTThe ultrafine grain sizes and high diffusivities in nanophase materials assembled from atomic clusters suggest that these materials may have a strong tendency toward superplastic mechanical behavior. Both small grain size and enhanced diffusivity can be expected to lead to increased diffusional creep rates as well as to a significantly greater propensity for grain boundary sliding. Recent mechanical properties measurements at room temperature on nanophase Cu, Pd, and TiO2, however, give no indications of superplasticity. Nonetheless, significant ductility has been clearly demonstrated in these studies of both nanophase ceramics and metals. The synthesis of cluster-assembled nanophase materials is described and the salient features of what is known of their structure and mechanical properties is reviewed. Finally, the answer to the question posed in the title is addressed.

Mechanical Nanocrystallization Surface Treatment on the Reheated 400MPa Ultrafine Grained Steel

2009 ◽  
Vol 79-82 ◽  
pp. 377-380
Author(s):  
Hong Yun Zhao ◽  
Guo Dong Wang ◽  
Chun Hua Xu ◽  
Feng Yuan Shu
Keyword(s):  
Mechanical Properties ◽  
Surface Treatment ◽  
Room Temperature ◽  
Performance Testing ◽  
Surface Form ◽  
Test Results ◽  
Ultrafine Grained ◽  
Before And After ◽  
Different Temperatures ◽  
Ultrafine Grained Steel

After reheated at different temperatures for 5 minutes, the 400MPa Ultrafine Grained Steel specimens were air-cooled to room temperature, and then carried out the mechanical nanocrystallization surface treatment and structure performance testing. On the basis of comparing the test results on the specimens before and after the mechanical nanocrystallization surface treatment, the process of mechanical nanocrystallization was analyzed briefly. The results show that: as the reheating temperature rising, the trend of grain size growing increases markedly, and the mechanical properties also drop down to different degrees; when the reheating temperature is around 800°C, because of the pearlite spheroidized significantly, its mechanical properties drop the most seriously; after the mechanical nanocrystallization surface treatment, not only its surface form a layer of fine nano-layer (about 100 nm) structure, but also its mechanical properties rise obviously, and the yield strength is over 450MPa.

Effect of Heat Treatment on the Mechanical Properties of Wrought Al-Zn-Mg-Cu Alloy Cast by Rapid Solidification

2013 ◽  
Vol 765 ◽  
pp. 496-500 ◽  
Author(s):  
Dawid Kapinos ◽  
Marcin Szymanek ◽  
Bogusław Augustyn ◽  
Maciej Gawlik
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rapid Solidification ◽  
Solution Heat Treatment ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Cu Alloy ◽  
Optimum Heat ◽  
Ultrafine Grain Structure ◽  
Alloy Cast

The article presents the change in mechanical properties of AlZn9Mg2.5Cu1.8 alloy resulting from the process of solution heat treatment and aging. The heat treatment was performed on a unique UMSA (Universal Metallurgical Simulator and Analyzer) device. The aim of the study was to determine optimum heat treatment parameters for the tested alloy of ultrafine grain structure obtained by Rapid Solidification (RS). To achieve this purpose, heat treatment to the T4 and T6 condition was carried out. The solution heat treatment was carried out at a constant temperature of 460 °C for 2 hours, while the time - temperature parameters of the aging process varied. The treatment undertaken resulted in improved mechanical properties.

Mechanical Properties of a Medium Carbon Low Alloy Steel Processed by Two Step Austempering Process

2010 ◽  
Vol 638-642 ◽  
pp. 3453-3458 ◽  
Author(s):  
Susil K. Putatunda ◽  
Abhijit Deokar ◽  
Gowtham Bingi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Alloy Steel ◽  
High Yield ◽  
Bainitic Steel ◽  
Low Alloy Steel ◽  
High Yield Strength ◽  
Medium Carbon

A new bainitic steel with a combination of exceptionally high yield strength and fracture toughness has been developed. This steel has been synthesized by austempering a medium carbon low alloy steel by a novel two-step austempering process. The influence of this two-step austempering on the microstructure and the mechanical properties of this new steel have been examined.

Effect of Pre-Aging on the Microstructure and Strength of Supersaturated AlZnMg Alloys Processed by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 501-506 ◽  
Author(s):  
Nguyen Q. Chinh ◽  
Jenő Gubicza ◽  
Tomasz Czeppe ◽  
Janos Lendvai ◽  
Zoltán Hegedűs ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solution Heat Treatment ◽  
Room Temperature ◽  
Shear Bands ◽  
Natural Aging ◽  
Al Alloys ◽  
Interesting Application ◽  
Subsequent Aging ◽  
Angular Pressing ◽  
Time Periods

This work is focused on the effect of the combination of natural aging and severe plastic deformation (SPD) produced by Equal-Channel Angular Pressing (ECAP) on the microstructure and strength of supersaturated AlZnMg alloys. Following a solution heat-treatment and quenching into water at room temperature, samples were naturally aged for different time periods and then processed by ECAP. The microstructure and mechanical properties of these samples are described and discussed. This investigation leads to proposing an interesting application of ECAP for supersaturated alloys. Using the shear bands created by ECAP in only one pass and applying appropriate subsequent aging treatments, composite-like microstructures can be achieved in conventional age-hardenanble Al alloys.

Microstructure and Mechanical Properties of Mg-RE-B Alloys

2011 ◽  
Vol 311-313 ◽  
pp. 2251-2254
Author(s):  
Le Ping Bu ◽  
Qing Tai Shen ◽  
Pei Wu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Room Temperature ◽  
Tensile Yield Strength ◽  
Ingot Metallurgy ◽  
Particle Structure ◽  
Promising Candidate ◽  
Excellent Mechanical Property ◽  
Before And After ◽  
Microstructure And Mechanical Property

The best is to read these instructions and follow the outline of this text. Mg-RE-B alloy with minuteness particle structure (MPS) were prepared by ingot metallurgy including as-cast and hot-extruded processing, and the microstructure and mechanical property of Mg-6RE-3B2O3 (wt%) alloys were investigated before and after hot-extruded. The Mg-RE-B alloy has satisfied grain size and particle structure, went with excellent mechanical property of tensile yield strength of 520 MPa and elongation of 5% at room temperature. The MPS Mg-RE-B alloy is a promising candidate among lightweight structural materials

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