Effect of Heat Treatment on Phase Transformation and Precipitation Behavior of Cu40Zn-1.0 Wt% Ti Brass via Powder Metallurgy

2011 ◽  
Vol 233-235 ◽  
pp. 2732-2735 ◽  
Author(s):  
Shu Feng Li ◽  
Hisashi Imai ◽  
Akimichi Kojima ◽  
Yoshiharu Kosaka ◽  
Koji Yamamoto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Powder Metallurgy ◽  
Solid Solubility ◽  
Chemical Potential ◽  
Volume Fraction ◽  
Powder Metallurgy Method ◽  
Micro Hardness ◽  
Precipitation Behavior ◽  
Β Phase

The effect of heat treatment on phase transformation, precipitation behavior and micro-hardness response of Cu40Zn-1.0Ti brass was investigated via powder metallurgy method. The volume fraction of α phase increased with elevated temperature, equaled to that of β phase at 400 °C, and reached to a maximum value of 55.9% at 500 °C. The solid solubility of Ti in Cu40Zn brass matrix decreased with elevated heat treatment temperature, showed high chemical potential for precipitates reaction in Cu40Zn brass. The micro-hardness of the BS40-1.0Ti brass was primarily dependent on the solid solubility of Ti, but also dependent on the phase ratio of α and β phase.

Micro-Hardness and Compression Strength of Particle Sizes Recycling Aluminium Alloy AA6061 Using Powder Metallurgy Method

2017 ◽  
Vol 887 ◽  
pp. 74-82 ◽  
Author(s):  
Ahmed Sahib Mahdi ◽  
Mohammad Sukri Mustapa ◽  
Abdul Latif M. Tobi ◽  
Izzuddin Zaman
Keyword(s):  
Particle Size ◽  
Aluminum Alloy ◽  
Powder Metallurgy ◽  
Aluminium Alloy ◽  
Compression Strength ◽  
Volume Fraction ◽  
Current Paper ◽  
Powder Metallurgy Method ◽  
Particle Sizes ◽  
Micro Hardness

The micro-hardness and compression of recycling aluminum alloy AA6061 were investigated as a function of the different volume fraction and particle sizes by using powder metallurgy method. Three different groups of volume fraction and particle size were used 21.5, 50 and 78.5 % and 25,63 and 100 μm respectively. The current paper highlight on the effect of the various of particle size on the compression strength and microhardness results. The results of compression strength and micro-hardness show that the type of the higher amount of the smaller size was obtained for higher value for each of compression strength and micro-hardness 195.66 MPa and 79.796 Hv respectively.While it was the lower values on the type of the smaller amount of the smaller size (132.05 MPa and 50.369 Hv) respectively.

scholarly journals Effect of Mo, V and Zr on the microstructure and mechanical properties of Ti2AlNb alloys

2020 ◽  
Vol 321 ◽  
pp. 08003
Author(s):  
Yujun Du ◽  
Xianghong Liu ◽  
Jinshan Li ◽  
Wenzhong Luo ◽  
Yongsheng He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Melting Process ◽  
Phase Region ◽  
Arc Furnace ◽  
Micro Hardness ◽  
Β Phase ◽  
Before And After ◽  
B2 Phase ◽  
O Phase

Small button ingots of Ti2AlNb alloys with different contents of Mo, V and Zr were melted by vacuum non-consumable arc furnace. Due to the rapid cooling rate during melting process, only β grains without precipitation were observed in most of the button ingots and no regular phenomenon was found. However, when the samples were heated to β phase region and then furnace cooled to room temperate, different morphologies and quantities of primary α phase and second O phase formed from the β grains of different samples. It is suggested that the morphology of α phase was changed from lamellar to quadrilateral with increasing V and the lath O increased with increasing Zr. Besides, the residual β/B2 phase increased with increasing Mo and V. The EDS results showed that Al and Zr were enriched in α phase whereas Nb, Mo and V were enriched in β/B2 phase. The micro-hardness of these samples before and after heat treatment was detected and the micro-hardness increased with increasing Zr and decreasing Mo and V.

Influence of Phases Stability on the Hydrogen Diffusion Coefficient in Ti-6Al-4V

2020 ◽  
Vol 986 ◽  
pp. 33-40
Author(s):  
Mohammed Kasim Mohsun
Keyword(s):  
Heat Treatment ◽  
Diffusion Coefficient ◽  
Titanium Alloys ◽  
Hydrogen Diffusion ◽  
Volume Fraction ◽  
Substantial Effect ◽  
Diffusion Annealing ◽  
Hydrogen Treatment ◽  
Β Phase ◽  
Hydrogen Diffusion Coefficient

For a unique microstructure creation, thermo-hydrogen treatment (THT), using hydrogen as a temporary alloying element within the heat treatment, is applied. This advanced heat treatment requires reliable data about the hydrogen diffusion coefficient (DH) for understanding diffusion kinetics and its effect on the mechanical behavior of the resulted phases. In this research, three different homogeneous microstructures were established for the investigation using different homogenization parameters. After that, the concentration of hydrogen, charged in the half-length of thin titanium rods via electrochemical hydrogenation, is specified. Then, a diffusion annealing heat treatment was carried out at different temperatures, leading to hydrogen diffusion in the hydrogenated specimens. Furthermore, DH was systematically determined using two methods including the explicit finite difference method (EFDM) and Matano technique (MT). For this purpose, Abaqus software was employed for modeling the hydrogen gradient established in the specimens. Additionally, scanning electron microscopy (SEM) was used for the microstructure examination in order to specify the influence of different hydrogen concentrations on the hydrogenated specimens. The experimental outcomes reveal a substantial effect of the β phase stability and grains sizes of the β and α phases on the hydrogen diffusion. Correspondingly, the results confirm that DH was independent of the hydrogen concentration, and obeys an Arrhenius-type temperature dependence. Furthermore, hydrogen diffusion in the α+β titanium alloys Ti-6Al-4V was slower in comparison to the hydrogen diffusion in the metastable β titanium alloys Ti-10V-2Fe-3Al. In conclusion, it was observed that DH is influenced by the previously performed heat treatments that determine the resulted microstructure types, and a slight influence of the volume fraction of the α phase on DH was observed as well.

Formation of a Novel X Phase in Mg–Gd–Zn–Zr Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 623-626 ◽  
Author(s):  
Y.J. Wu ◽  
Li Ming Peng ◽  
X.Q. Zeng ◽  
D.L. Lin ◽  
W.J. Ding
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformation ◽  
Grain Boundaries ◽  
Solution Heat Treatment ◽  
Long Period ◽  
Β Phase ◽  
Lpso Structure ◽  
Zr Alloy ◽  
Zr Alloys

The coherent fine-lamellae consisting of the 2H-Mg and the 14H-type long period stacking ordered (LPSO) structure within α'-Mg matrix have been observed in an as-cast Mg–Gd–Zn–Zr alloy. During subsequent solid solution heat treatment at 773 K, in addition to the lamellae within matrix, a novel lamellar X phase [Mg–(8.37±1.0)Zn–(11.32±1.0)Gd] with the 14H-type LPSO structure was transformed from the dendritical β phase. The 14H-type LPSO structure existing in Mg–Gd–Zn–Zr alloys derives from two variant ways: formation of the 14H-type LPSO structure comes from two variant means: i.e., the formation within matrix and the phase transformation from the β phase to the X phase in grain boundaries.

An investigation on thermodynamics and kinetics of η phase formation in Nb-modified iron-nickel base A286 superalloy

2020 ◽  
Vol 118 (1) ◽  
pp. 105
Author(s):  
Reza Soleimani Gilakjani ◽  
Seyed Hossein Razavi ◽  
Masoumeh Seifollahi
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Phase Formation ◽  
Volume Fraction ◽  
Treatment Time ◽  
Diffusion Activation Energy ◽  
Phase Volume Fraction ◽  
Titanium Nickel ◽  
Nickel Base ◽  
Microstructural Studies

In this study, precipitation of η phase (Ni3Ti) in conventional and Nb-modified (Nb-A286) A286 superalloys was evaluated at different aging times and temperatures. The TTP curve of the η phase formation was plotted using thermodynamic analyses, kinetics and microstructural studies. Depending on temperature and heat treatment, the η phase precipitated at the grain boundaries or twin sites, as a result of the γ′ phase or matrix austenite transformation. Heat treatment of conventional A286 superalloy and Nb-A286 was performed within a temperature range of 650 to 900 °C for 2 to 30 h. The η phase transformation was evaluated by scanning electron microscope (SEM) which is equipped to energy dispersive X-ray spectroscopy (EDS) and optical microscopy (OM). In the analyses based on thermodynamic calculations, the interaction of the Gibbs free energy of η phase formation and the diffusion activation energy of the elements, especially titanium and niobium, was considered. The microstructural studies showed that increasing the heat treatment time results in increasing the volume fraction of the η phase. By increasing the aging temperature to 840 and 860 °C for conventional A286 superalloy and Nb-A286 superalloy, respectively, the η phase volume fraction increased, however, further increase led to volume fraction decrease. The results of the thermodynamic analyses showed the tip of the TTP diagrams at temperatures of 860 and 820 °C for the A286 and Nb-A286 alloys, respectively. Investigation of kinetics calculations showed that η phase transformation depends on the diffusion of titanium, nickel, and niobium.

Effect of Pore Forming Agent on Microstructures and Properties of Porous Molybdenum

2013 ◽  
Vol 761 ◽  
pp. 157-160
Author(s):  
Zhen Lin Lu ◽  
Xiao Jie Rao ◽  
Xiao Feng Xu
Keyword(s):  
Sodium Chloride ◽  
Powder Metallurgy ◽  
Influencing Factors ◽  
Fracture Strength ◽  
Volume Fraction ◽  
Transmission Rate ◽  
Powder Metallurgy Method ◽  
Compressive Fracture ◽  
Hydrogen Carbonate ◽  
Ammonium Hydrogen

The porous molybdenum was prepared by addition of pore forming agent and powder metallurgy method. The results show that the species and amount of pore forming agent are the primary influencing factors for the microstructures and properties of porous molybdenum. The pore shapes in porous molybdenum are regular and uniformly distributed. The porosity of porous molybdenum would be the largest and the transmission rate would be the best when sodium chloride was selected as pore forming agent. The compressive fracture strength of porous molybdenum would be more than 30MPa when the ammonium hydrogen carbonate was selected as pore formimg agent and its addition was 70 % (volume fraction). But the porosity would be the lowest.

Microstructure and Mechanical Properties of Fly Ash Al-25Mg Composites Processed by Powder Metallurgy Method

2010 ◽  
Vol 152-153 ◽  
pp. 545-549
Author(s):  
Qing Ping Wang ◽  
Yu Cheng Wu ◽  
Fan Fei Min
Keyword(s):  
Fly Ash ◽  
Powder Metallurgy ◽  
Abrasive Wear ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Aluminum Matrix ◽  
Ash Content ◽  
Aluminum Matrix Composites ◽  
Al Alloy ◽  
Powder Metallurgy Method

Fly ash particles reinforced aluminum matrix composites were fabricated by powder metallurgy method. The influence of different fly ash content on hardness, the friction and wear behavior of the composites were investigated at a constant sliding velocity of 400r/min. The worn surfaces of composites were observed by scanning electron microscope, and worn mechanism of composites was discussed. The results showed that the hardness of composites increased first and then decreased with fly ash content increasing. Under the lower loads and at the lower fly ash content, the friction co-efficient is steadily lower than that of Al alloy matrix. The wear resistance of composites increased with the volume fraction of fly ash particles and the wear mechanism was characterized as abrasive wear and adhesive wear.On the other hand, the wear mechanisms in the composites have been transformed with increasing load and fly ash volume; it mainly was delamination wear and abrasive wear.

Metastable Phase Transformations in Ti-40Al-10V Alloy

1994 ◽  
Vol 364 ◽  
Author(s):  
G. Shao ◽  
P. Tsakiropoulos ◽  
A. P. Miodownik
Keyword(s):  
Phase Transformation ◽  
Phase Transformations ◽  
Volume Fraction ◽  
Metastable Phase ◽  
Equilibrium Phase ◽  
Rapid Quenching ◽  
Β Phase ◽  
Transformation Sequence ◽  
Melt Spun ◽  
Melt Spun Ribbons

AbstractThe microstructures in arc melted ingots and melt spun ribbons have been investigated by electron microscopy and thermodynamic modelling has been used to study the phase transformations. In the ingot, solidification starts with the bcc β phase and at room temperature the structure consists of B2, ωordered, γ and α2 phases. The calculated equilibrium phase transformation sequence during cooling is L → L+ β→β→β + α→β2+α → α+β2+γ → α2+γ + B2. The phase transformation sequence is dramatically changed by rapid quenching from the melt. Athermal ordered w phase is formed in metastable B2 and the α→α2 ordering process is completely suppressed in the melt spun ribbons. The volume fraction of the α precipitates is also dependent on cooling rates.

Effect of Addition of Al & Ca and Heat Treatment on the Cast Mg-6Zn Alloy

2013 ◽  
Vol 765 ◽  
pp. 33-37 ◽  
Author(s):  
S.S. Joshi ◽  
M.S. Mohan ◽  
S. Seshan ◽  
S. Kumar ◽  
S. Suwas
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Boundary Phase ◽  
Al Content ◽  
Β Phase ◽  
The Matrix

In the present investigation, the effect of addition of Al and small amounts of Ca as well as the effect of heat treatment has been investigated on microstructure, tensile properties and corrosion behaviour of Mg-6Zn alloy produced by squeeze casting. The Mg-6Zn-1Al (ZA61) alloy consisted of α-Mg grains and MgZn (β) phase at the grain boundaries with a much higher strength and ductility than pure Mg. The addition of 0.1 and 0.5 wt% Ca to the ZA61 alloy refined the grain size and increased the volume fraction of the grain boundary phase but did not change the nature of the phase. Consequently, strength increased without much reduction in ductility. The increase in Al content of the alloy to 4 wt% (ZA64) changed the grain boundary phase to Al5Mg11Zn4 (Φ) phase, increased its volume fraction and refined the grain size as compared to ZA61 alloy. Consequently, strength increased with a reduction in ductility. On heat treatment of ZA61+0.5Ca and ZA64 alloys, the volume fraction of grain boundary phases decreased, fine precipitates were obtained in the matrix and the grain size increased. Thus, higher strength with a lower ductility was obtained on heat treatment but the ductility of both the alloys was still higher than that of pure Mg. Thus, 130 MPa 0.2%PS, 225 MPa UTS and 4.9% elongation to fracture could be obtained for the squeeze cast ZA64 alloy in the T6 condition, which are very good tensile properties for a cast Mg alloy. Increase in Al content and heat treatment reduced the corrosion resistance and addition of Ca improved it. The highest corrosion rate was observed to be 0.85 mm/year for the ZA64 alloy in the T6 condition.

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