Brass H62 Hot Extrusion of Micro Gear

2011 ◽  
Vol 704-705 ◽  
pp. 236-239
Author(s):  
Xiang Ru Liu ◽  
Xu Dong Zhou
Keyword(s):  
Hot Extrusion ◽  
Extrusion Process ◽  
Optical Microscope ◽  
Flow Lines ◽  
Β Phase ◽  
Α Phase ◽  
Internal Part ◽  
Anisotropic Mechanical Properties ◽  
Mems Technology ◽  
Circle Diameter

Gears are very important and widely used driving components in mechanical instruments, and the demands of micro-gears are increasing more and more active as the MEMS technology develops in recent years. In this paper, a brass micro gear, which modulus m = 0.125 mm, pressure angle α = 20°, number of teeth z = 6, addendum circle diameter d = 1 mm, hot extruded from brass H62 billet with size Φ3×3 mm at 650°C was studied by experimental method. The microstructure of the micro gear was observed by scanning electron microscope and optical microscope, and the conclusions are as follows: the fiber flow lines within the micro-gear were formed by the extrusion, so that the anisotropic mechanical properties of the micro-gear was happened; The tissue distribution of micro-gear was that, the surface of the gear is almost entirely α-phase, while the internal part of the gear was the mixture of α-phase and β-phase, because the α-phase with lower hardness flowing outward to the surface of the gear during the extrusion process.

Microstructure Evolution of near α Titanium Alloy during Multi-Step Thermomechanical Deformation Process

2021 ◽  
Vol 1035 ◽  
pp. 305-311
Author(s):  
Qing Shan Liu ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Cong Cong Wang ◽  
Peng Qi ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Strain Curve ◽  
Optical Microscope ◽  
Phase Content ◽  
Β Phase ◽  
Α Phase ◽  
Gleeble 3500

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation

Crystallographic Peculiarities of β-α Transformation in Brass Induced by Hot Extrusion

2020 ◽  
Vol 299 ◽  
pp. 541-545
Author(s):  
Mikhail L. Lobanov ◽  
S.V. Danilov ◽  
Vladimir I. Pastukhov
Keyword(s):  
Coincident Site Lattice ◽  
Hot Extrusion ◽  
Air Cooling ◽  
Orientation Microscopy ◽  
Β Phase ◽  
Α Phase ◽  
Orientation Relations ◽  
Main Components ◽  
Relationship Of ◽  
Significant Concentration

Structure-texture states in brass rods after hot extrusion and air-cooling have been investigated with the orientation microscopy (EBSD). In the examined samples, a significant concentration of β-phase with the lattice, close to bcc and fcc α-phase, has been detected. The β-phase texture consisted of the main components: two close to {110}<110> and {001}<110>. The α-phase texture consisted of the main components: close to {001}<100> and two close {110}<111>. The analysis of crystallographic relationship of the texture components of β-and α-phases demonstrates that they may all be obtained, in accordance with the orientation relations, which are intermediate between the Kurdjumov-Sachs and Nishiyama-Wasserman types It is assumed that β-α transformation began in β-phase at coincident site lattice Σ3 and Σ33a boundaries.

Fabrication of Carbon Nanotube Reinforced Aluminum Composite by Powder Extrusion Process

2007 ◽  
Vol 534-536 ◽  
pp. 889-892 ◽  
Author(s):  
Junichi Yuuki ◽  
Hansang Kwon ◽  
Akira Kawasaki ◽  
Akira Magario ◽  
Toru Noguchi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Extrusion ◽  
High Strength ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Optical Microscope ◽  
Al Alloy ◽  
Aluminum Composite ◽  
Very High

This paper describes a fabrication process of Al/CNT composites and investigated their mechanical properties. CNT is a very useful reinforcement for composites since it has a very high strength and very high Young’s modulus. However, it is very difficult to distribute CNT in a metal matrix. Natural rubber was used as an elastomer and mixed with Al powder and CNT precursors to improve the distribution of the CNT in Al matrix. The resulting powder mixture was filled into Al alloy billets and encapsulated in vacuum atmosphere. The billets were then extruded with different extrusion ratios of 5, 10 and 20 at 673K. The composites were observed under optical microscope and FE-SEM, and the mechanical properties were evaluated by Vickers hardness and tensile tests. We succeeded in obtaining fully densified and finely extruded rod of Al/CNT composites of well distributed CNT by hot extrusion process. Observation of post extrusion micro structures revealed that CNT were not damaged by the hot extrusion process and their Vickers hardness and tensile strengths obtained were about twice compared to pure Al.

The Use of Superplastic Alloy of the Eutectic of Lead–Tin for the Analysis of Hot Extrusion Process

1972 ◽  
Vol 94 (4) ◽  
pp. 1060-1066 ◽  
Author(s):  
A. H. Shabaik ◽  
A. M. Virani
Keyword(s):  
Material Properties ◽  
Room Temperature ◽  
Hot Extrusion ◽  
Flow Fields ◽  
Extrusion Process ◽  
Flow Function ◽  
Flow Lines ◽  
Dynamic Similarity ◽  
Superplastic Alloy ◽  
Good Agreement

The dynamic similarity of two geometrically similar extrusion processes was examined. The flow lines, values of the flow function ψ, and velocity components were compared for the hot extrusion of SAE 1018 steel at 1800 deg F and 10 ips, and the superplastic eutectic alloy of lead–tin at room temperature and 0.088 ipm. The comparison showed a good agreement between the two cases and that dynamic similarity of the flow fields was achieved under the previous conditions. Material properties were examined and results indicated that similarity of the mechanical properties is necessary for the dynamic similarity of the flow fields.

Influence of Duplex Annealing on the Microstructure and Mechanical Properties of Ti62421S Titanium Alloy Plate

2015 ◽  
Vol 816 ◽  
pp. 804-809 ◽  
Author(s):  
Xiao Yun Song ◽  
Yong Ling Wang ◽  
Wen Jing Zhang ◽  
Song Xiao Hui ◽  
Wen Jun Ye
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Alloy Plate ◽  
Β Phase ◽  
Α Phase ◽  
Microstructure And Mechanical Properties

The effects of different duplex annealing treatments on the microstructure and mechanical properties of Ti62421S alloy plate were studied by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and tensile tests, The experimental results indicated that the original microstructure of Ti62421S was composed of primary α phase (αp) and intergranular β phase. With the increase of first-stage annealing temperature, the volume fraction of equiaxed αp phase decreased. In contrast, the content of transformed β structure (βt) increased, and the width of lamellar secondary α phase (αs) in βt increased. Consequently, the yield strength (σ0.2) and ultimate tensile strength (σb) at room temperature and 600°C increased, while the elongation (δ5) declined. After 1000°C/2h/AC+ 600°C/2h/AC duplex annealing treatment, Ti62421S alloy plate showed superior tensile properties. The values of σb and δ5 at room temperature reached 1133MPa and 6%, as well as the value of σb at 600°C exceeded 710MPa.

Temperature Effects of ECAP and Annealing after ECAP on Microstructure of TA15 Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 332-336
Author(s):  
Yan Zhao ◽  
Hong Zhen Guo ◽  
Zhi Feng Shi ◽  
Yong Qiang Zhang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Temperature Effects ◽  
Optical Microscope ◽  
Phase Region ◽  
Pressing Temperature ◽  
Angular Pressing ◽  
Β Phase ◽  
Α Phase ◽  
Transmission Electron ◽  
Ta15 Alloy

A study was conducted by optical microscope (OM) and transmission electron microscope (TEM) on the microstructure evolution of TA15 alloy by severe plastic deformation (SPD) and annealing after SPD. In this study, equal channel angular pressing (ECAP) was taken as the method of SPD. The chief aim of the present work is to investigate the temperature effects of ECAP and annealing after ECAP on microstructure of TA15 alloy. The results indicate that equiaxed microstructure has been obtained by ECAP at the temperatures of α+β phase region, and that with the increase in pressing temperature, equiaxed grains have become coarser and the content of α phase has reduced. β grains have been coarsened severely since the pressing temperature was above the α-β transformation temperature (Tβ). Annealed at proper temperature after ECAP, the α phase of TA15 alloy has been more homogeneous, prior α phase has been well globularized, and grains have not grown obviously. According to the testing of TA15 alloy, the optimized temperature parameters of ECAP and annealing after ECAP are 900°C and 700°C. Observation and Analysis of the TEM morphological images illustrate that a quantity of twinning deformations have been produced by ECAP at the temperatures below Tβ, which leads to the continued plastic deformation through the restarting of many slip bands.

Effects of Micro and Nano-Size Al2O3 Particle Reinforcement on Mechanical Behaviour of Extruded Aluminum Alloy Matrix Composite

2015 ◽  
Vol 787 ◽  
pp. 617-621 ◽  
Author(s):  
R. Senthilkumar ◽  
N. Arunkumar ◽  
M. Manzoor Hussian
Keyword(s):  
Aluminum Alloy ◽  
Hot Extrusion ◽  
Weight Fraction ◽  
Extrusion Process ◽  
Optical Microscope ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Nano Composite ◽  
Weight Percentage ◽  
Nano Size

Aluminum alloy (AA2014) matrix composites reinforced by different weight percentage of aluminum oxide (Al2O3) in micro and nano sizes were fabricated through powder metallurgy route followed by hot extrusion process. Seven different aluminium composites with varying percentages of nano and micron sized alumina particles varying from 1% to 10% were evaluated in addition to monolithic alloy. The microstructure of nano-composite and monolithic alloys were examined by optical microscope and scanning electron microscope (SEM) equipped with an energy dispersive X-ray analysis (EDAX). In addition, the effects of weight fraction of the reinforcement matrix on mechanical properties were evaluated. The results have indicated that, a significant improvement in hardness of the nano composite was found in case of nano-composite with 8% of micro Al2O3 and 2% of nano Al2O3 particles by the addition of reinforcement.

Formation of the Surface Oxide Film on as-Cast Mg-7Li Alloy

2011 ◽  
Vol 239-242 ◽  
pp. 1082-1087
Author(s):  
Jun Gang Li ◽  
Ying Lv ◽  
Mu Qin Li ◽  
Zun Jie Wei ◽  
Xiang Cai Meng
Keyword(s):  
Oxide Film ◽  
Optical Microscope ◽  
Surface Oxide ◽  
Surface Oxide Film ◽  
Thin Oxide Film ◽  
Β Phase ◽  
Α Phase ◽  
Lithium Peroxide ◽  
Materials Used ◽  
Increasing Temperature

The excellent properties of Mg-Li alloys make them suitable light fabrication materials used extensively in many applications. The microstructure and the surface oxide film at different temperature of as-cast Mg-7Li alloy were investigated by optical microscope(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and electronic analytical balance. Results showed that Mg-7Li alloy was composed of mainly α phase and β phase. With increasing temperature, the morphology of the alloy surface varied from the formation of a very thin oxide film, large amounts of oxide particles to the thick and coarse film with a mass of cellular protuberances in size of 40-80μm. The ratio of oxidation weight gains rose from 0.08% to 11.58%. The surface oxide film consisted of mainly magnesium oxide(MgO) phase and lithium peroxide(Li2O2) phase, resulting from the reaction of oxygen with Mg and Li. The volume of the oxides on β phase greater than that on α phase led to the formation of cellular protuberance on the surface of Mg-7Li alloy at high temperature.

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

1995 ◽  
Vol 74 (06) ◽  
pp. 1501-1510 ◽  
Author(s):  
J Kuiper ◽  
H van de Bilt ◽  
U Martin ◽  
Th J C van Berkel
Keyword(s):  
Plasminogen Activator ◽  
Liver Cells ◽  
The Novel ◽  
Uptake Mechanism ◽  
Liver Uptake ◽  
Lysosomal Compartment ◽  
Β Phase ◽  
Α Phase ◽  
Parenchymal Liver

SummaryThe catabolism of the novel plasminogen activator reteplase (BM 06.022) was described. For this purpose BM 06.022 was radiolabelled with l25I or with the accumulating label l25I-tyramine cellobiose (l25I-TC).BM 06.022 was injected at a pharmacological dose of 380 μg/kg b.w. and it was cleared from the plasma in a biphasic manner with a half-life of about 1 min in the α-phase and t1/2of 20-28 min in the β-phase. 28% and 72% of the injected dose was cleared in the α-phase and β-phase, respectively. Initially liver, kidneys, skin, bones, lungs, spleen, and muscles contributed mainly to the plasma clearance. Only liver and the kidneys, however, were responsible for the uptake and subsequent degradation of BM 06.022 and contributed for 75% to the catabolism of BM 06.022. BM 06.022 was degraded in the lysosomal compartment of both organs. Parenchymal liver cells were responsible for 70% of the liver uptake of BM 06.022. BM 06.022 associated rapidly to isolated rat parenchymal liver cells and was subsequently degraded in the lysosomal compartment of these cells. BM 06.022 bound with low-affinity to the parenchymal liver cells (550 nM) and the binding of BM 06.022 could be displaced by t-PA (IC50 5.6 nM), indicating that the low-density lipoprotein receptor-related protein (LRP) could be involved in the binding of BM 06.022. GST-RAP, which is an inhibitor of LRP, could in vivo significantly inhibit the uptake of BM 06.022 in the liver.It is concluded that BM 06.022 is metabolized primarily in the liver and the kidneys. These organs take up and degrade BM 06.022 in the lysosomes. The uptake mechanism of BM 06.022 in the kidneys is unknown, while LRP is responsible for a low-affinity binding and uptake of BM 06.022 in parenchymal liver cells.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

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