The roles of stress state and pre-straining on Swift effect for an extruded AZ31 Mg alloy

The Swift effect of Mg alloy is sensitive to initial texture.However,dislocation slip is the main deformation mechanism during torsion of Mg alloy.The underlying relation of Swift effect and dislocation slip is still not clarified.The effect of stress state and pre-straining on Swift effect was studied experimentally during free-end torsion for an extruded AZ31 alloy.The free-end torsion was performed with axial tension and compression stress which is lower than yield stress.It is found that the transition of axial deformation from contraction to elongation occurs when the axial stress changes from negative to positive.The pre-dislocations introduced by pre-tension promote axial shortening during torsion.While the pre-twins introduced by pre-compression are inhibition of axial shortening.The change of axial deformation is attributed to competition between twinning and prismatic slip.The axial shortening of extruded Mg alloy is generated by tensile twinning leading to c-axis strain.In contrast,the axial elongation can be generated by the activation of prismatic slip.The magnitude of axial strain generated by twinning is larger than that by prismatic slip.Moreover,the occurrence of detwinning results in axial elongation at low shear strain.

Numerical study on mixing performance of screw elements in intermeshing counter-rotating and co-rotating twin-screw extrudes

The flow process of unplasticized polyvinyl chloride （U PVC） through the mixing zone of intermeshing counter rotating and co rotating twin screw extruders （TSEs） were numerically simula ted by the finite element method. Three dimensional isothermal flow field of U-PVC in two kinds of TSE was calculated. The mixing performance of the screw elements of the extruders was statistically analyzed by particle tracking method. The dispersive mixing performance was characterized by the mixing index, the logarithm of stretching, and the segregation scale. The distributive mixing per forulance was characterized by the resident time distribution. The results indicate that the counter rotating TSE can build higher pressure and generate higher axial velocity and shear rate, whereas the co rotating TSE has better performance in dispersive and distributive mixing.

Low cycle fatigue behavior of the extruded AZ80 magnesium alloy under different strain amplitudes and strain rates

Low cycle fatigue behavior of extruded AZ80 magnesium alloy was investigated under uniaxial tension-compression at different strain amplitudes and strain rates.The results show that the extruded AZ80 magnesium alloy exhibits cyclic hardening at strain amplitudes ranging from 0.4%to 1.0%,the asymmetry of hysteresis loops becomes increasingly obvious when the strain amplitude increases.Higher strain rates correspond to higher stress amplitudes,high mean stresses and short fatigue life.{10–12}extension twins play a role in the cyclic deformation under higher strain amplitudes(0.8%,1.0%).The relationship between total strain energy density and fatigue life can be described by the modified Morrow model.The effect of strain rate on the fatigue life can also be predicted by the model.

Dynamic compressive property and failure behavior of extruded Mg-Gd-Y alloy under high temperatures and high strain rates

For the purpose of investigating the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates,the Split Hopkinson Pressure Bar(SHPB)was used for investigating dynamic mechanical properties of extruded Mg-Gd-Y Magnesium alloy at ambient temperature(300 K),200℃(473 K)and 300℃(573 K)temperature.The samples after compression were analyzed by scanning electron microscope(SEM)and metallographic microscope.Dynamic mechanical properties,crack performance and plastic deformation mechanism of extruded Mg-Gd-Y Magnesium alloy along the extrusion direction(ED)were discussed.The results show that,extruded Mg-Gd-Y Magnesium alloy has the largest dynamic compressive strength which is 535 MPa at ambient temperature(300 K)and strain rate of 2826 s^(−1).When temperature increases,dynamic compressive strength decreases,while ductility increases.The dynamic compression fracture mechanism of extruded Mg-Gd-Y Magnesium alloy is multi-crack propagation and intergranular quasi-cleavage fracture at both ambient temperature and high temperature.The dynamic compressive deformation mechanism of extruded Mg-Gd-Y Magnesium alloy is a combination of twinning,slipping and dynamic recrystallization at both ambient temperature and high temperature.

Simulation of Polymer Melt Flow Fields in Intermeshing Co-Rotating Three-Screw Extruders

Three-dimension isothermal flows of polymer melt in the kneading blocks of triangularly-arranged and parallelly-arranged intermeshing co-rotating three-screw extruders are simulated using the finite element package POLYFLOW. Based on the velocity fields calculated, the particle trajectories in both machines are visualized using particle tracking technique. The numerical results indicate that the flow patterns in three-screw extruders are similar to those in twin-screw extruders. The triangularly-arranged three-screw extruder has the largest pumping capacity and also the highest extrusion stability in terms of flowrate fluctuation with screw rotation. The instantaneous mixing and cumulative residence time distribution （RTD） characteristics are also analyzed and compared with traditional intermeshing co-rotating twin-screw extruders. It is shown that the start section of the cumulative RTD curve for the triangularly-arranged machine has a small shoulder, which is attributed to the faster flow in the central region of this type of extruder.

Texture evaluation in warm deformation of an extruded Mg-6Al-3Zn alloy

To assess the effect of strain and strain rate on texture evolution of an extruded Mg–6Al–3Zn alloy,compression tests were carried out.Samples were prepared in the extrusion direction(ED)and normal direction(ND).The compression tests were performed at 250℃ and with different strain rates of 0.01 sec−1 and 1 sec−1 and different strains.Microstructural observation and texture investigation show that at early stages of deformation,extension twins lead to the development of strong basal texture intensity along rolling direction(RD)in ED samples and contraction twins result in texture evolution along transverse direction(TD)in ND samples.Also,microstructural investigation at high strains reveals that dynamic recrystallization occurs in both samples and consequently the basal texture intensity has been decreased.

Effects of Y content and temperature on the damping capacity of extruded Mg-Y sheets

The damping behavior of extruded Mg-xY(x=0.5,1.0,3.0 wt.%)sheets were investigated in detail concerning the effects of Y addition and temperature,and the relationship between damping capacity and yield strength was discussed.At room temperature(RT),with Y content increasing from 0.5%to 3.0%,the damping capacity(Q-1)significantly decreased from 0.037 to 0.015.For all the studied sheets,the relationship between strain amplitude and Q-1 fitted well with the Granato and Liicke(G-L)dislocation damping model.With temperature increased,the G-L plots deviated from linearity indicating that the dislocation damping was not the only dominate mechanism,and the grain boundary sliding(GBS)could contribute to damping capacity.Consequently,the Q-1 increased remarkably above the critical temperature,and the critical temperature increased significantly from 50℃ to 290℃ with increasing Y contents from 0 to 3.0wt.%.This result implied that the segregation of Y solutes at grain boundary could depress the GBS,which was consistent with the recent finding of segregation tendency for rare-earth solutes.The extruded Mg-IY sheet exhibited slightly higher yield strength(Rp0.2)and Q-1 comparing with high-damping Mg-0.6Zr at RT.At an elevated temperature of 325℃,the Mg-IY sheet had similar Q-1 but over 3 times larger Rp0.2 than that of the pure Mg.The present study indicated that the extruded Mg-Y based alloys exhibited promising potential for developing high-performance damping alloys,especially for the elevated-temperature application.

A comparison study of Ce/La and Ca microalloying on the bio-corrosion behaviors of extruded Mg-Zn alloys

The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current study.Compared with single Ca or Ce/La addition,the Ca-Ce/La cooperative microalloying results in an outstanding grain refinement,because the fine secondary phase particles effectively hinder the recrystallized grain growth.The coarse Ca2Mg6Zn3 phases promote the formation of Ca3(PO4)2 or hydroxyapatite particles during the immersion process and accelerate the dissolution of the corrosion product film,which destroys its integrity and results in the deterioration of anti-corrosive performance.The Ce/La elements can be dispersed within the conventional Mg7Zn3 phases,which reduce the internal galvanic corrosion between Mg matrix and the secondary phases,leading to an obvious improvement of corrosion resistance.Therefore,the Ca-Ce/La cooperative microalloying achieves a homogenous fine-grained microstructure and improves the protective ability of surface film,which will pave a new avenue for the design of biomedical Mg alloys in the coming future.

Gluten-Free Flat Bread and Biscuits Production by Cassava, Extruded Soy Protein and Pumpkin Powder

In recent years, there has been an increase in demand of gluten free products that are suitable for people with celiac disease. The present study was carried out to produce gluten free flat bread and biscuits with good quality. The ingredients under this study were cassava flour, rice flour, extruded soy protein (ESP) and pumpkin powder. Four levels of ESP were used for production of flat bread and biscuits: 2.5%, 5%, 7.5% and 10% for flat bread and 5%, 10%, 15% and 20% levels for biscuits. Results of flat bread samples showed that protein, fat, ash and fiber contents increased in all samples as increasing the level of ESP. Flat bread at level 10% ESP had the highest value of β-carotene. Alkaline water retention capacity (AWRC) at zero time and 24 h of flat bread storage had high values for levels 2.5% and 5% ESP. Water holding capacity (WHC) increased insignificantly by increasing the level of ESP. Color measurements revealed that the lightness decreased and the redness increased with increasing the level of ESP. Sensory evaluation of flat bread revealed that 2.5% followed by 5% ESP level had high score of overall acceptability. Physical properties of biscuits indicated that as the level of ESP increased the diameter, thickness, volume and specific volume decreased. Biscuits sample with 20% ESP had the highest values of protein, fat, ash and fiber but the lowest in total carbohydrates. Also β-carotene and vitamin A content increased in biscuit samples. Caloric values of biscuits in all treated samples were lower than control. Lightness decreased while redness increased with increasing the level of ESP. Data of texture profile analysis (TPA) showed that hardness and adhesiveness (g) increased as ESP level increased. Sensory evaluation of biscuits showed that addition of ESP at 20% level decreased significantly texture score from 9.51 to 6.61 (P < 0.05) but insignificantly affected the other sensory scores.

Study on Hardware-in-loop Simulation of Twin-screw Extruder Experiment System

In order to facilitate the teaching of industrial processes and experiments on the twin-screw extruder control debugging,and be closer to the actual testing,to reduce the debugging costs and the risk of debugging process,the paper designs a hardware-in-loop simulation of twin-screw extruder experiment system which is closer to scene,low cost and high safety.The system through the establishment of twin-screw extruder’s mathematical model on computer to simulate the realistic system and there is hardware practicality in the computer simulation loop.The hardware based on C8051F020 can operate in the simulation loop in real time.In computer software design, we desigh man-machine interface that is intuitive and easy to operate,can reflect twin-screw extruder main operation information vividly.Finally,twin-screw extruder’s 3 heater temperature mathematical model and PID incremental control algorithm are presented.

Creep Induced Phase Transformation in Extruded Zn-Al Alloy

Phase transformation and microstructural change of an extruded eutectoid Zn-Al alloy Zn76Al22Cu2 (wt pct) were investigated during creep testing by using SEM and X-ray diffraction techniques. Creep induced decomposition of a metastable η'T phase and a four phase transformation, α+ ε →T' +η, occurred during the creep testing. Also a microstructural change was observed from a lamellar structure into a spheroidized structure in the rupture part of the extruded alloy. It provided evidence of creep induced phase transformations which occurred in ageing process. The mechanism of creep rupture of the extruded Zn-Al alloy was also discussed.

Extruded Corn Meal as a Partial Replacement for Steam Flaked Corn in Finishing Diets for Feedlot Cattle: Growth Performance and Digestive Function of Feedlot Cattle

Sixty-four Holstein steers (247 ± 4 kg) were used in a 70-d experiment to evaluate the effects of partial replacement of steam flake corn (SFC) with extruded corn meal (EC) on growth performance and dietary net energy. Treatments consisted of a steam flaked corn-based finishing diet containing 0%, 10%, 20%, or 30% EC, where EC replaced 0%, 15%, 30%, or 45% of SFC (DM basis). Replacement of SFC with increasing levels of EC did not affect (P > 0.10) ADG, DMI, and gain efficiency. When EC replaced 15% to 30% of SFC, observed dietary NE was 99% of expected. Whereas, when EC replaced 45% of SFC, observed dietary NE was 94% of expected. Four Holstein steers (210 ± 7 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate treatment effects on characteristics of digestion. Partial replacement of SFC with EC did not affect (P > 0.10) flow of undegraded feed N and microbial N and to the small intestine, and ruminal microbial N efficiency (g microbial N/kg OM fermented). Likewise, there were no treatment effects (P > 0.10) on ruminal digestion of OM, NDF, starch and feed N. As expected, total tract digestion of starch for all treatments exceeded 99%. However, partial replacement of SFC with EC decreased total tract digestion of DM and OM (linear effect, P = 0.02), and dietary DE (linear effect, P = 0.03). These effects were more pronounced where EC replaced 45% of SFC. Partial replacement of SFC with EC did not affect (P > 0.10) ruminal pH, total VFA concentration, molar proportions of acetate, propionate, and butyrate, and estimated methane production. It is concluded that partial replacement of SFC with EC does not have a beneficial effect on ruminal microbial efficiency and digestive function. The feeding value of extruded corn for feedlot cattle is comparable to that of steam flaked corn provided the inclusion rate does not exceed 20% of diet dry matter.

Formulation, Preparation and Evaluation of Low-Cost Extrude Products Based on Cereals and Pulses

Protein-energy malnutrition among children is the major health challenges and it may be related to low nutritional quality of traditional complementary foods and high cost of quality protein-based complementary foods. The aim of this study was formulation, preparation and evaluation of low-cost extruded products based on cereals and pulses. Composite flours were prepared using cereals and pulses, then formulated and extruded by a twin screw extruder in Osmania University, Hyderabad, India. Data were analyzed by SPSS software. Results showed: the protein contents of extruded formulas B, D and F were in the highest values. Carbohydrate in the extruded formula A was significantly higher than others. The lowest amount of ash and crude fiber were observed in the formula A. Content of energy in the extruded formulas E, F and C was higher;mean (SD) of Fe content in the extruded formula B, D and F was in the higher ranks among others. Calcium content in the extruded formulas C, E and F was in the highest amounts. Magnesium content in the extruded formulas B, D and F was higher than others. Cu content in the extruded formula C, D, B and F was higher than others. Manganese content in the extruded formulas B, C and F, and zinc content in the formulas B, D and F were higher than others. Tap density showed the lowest amount in the formula B, D and F, while their bulk density was higher. WHC was in the highest amount in the extruded formula A, while WSI in the extruded formula B, D and followed by F was in the highest amount. The mean scores of sensory evaluation of extruded products F showed that this combination has significantly better colour, flavour, texture and overall acceptability than others.

A review of mid-frequency vibro-acoustic modelling for highspeed train extruded aluminium panels as well as the most recent developments in hybrid modelling techniques

The present paper reviews the vibro-acoustic modelling of extruded aluminium train floor structures including the state-of-the-art of its industrial applications, as well as the most recent developments on mid-frequency mod- elling techniques in general. With the common purpose to predict mid-frequency vibro-acoustic responses of stiffened panel structures to an acceptable accuracy at a reasonable computational cost, relevant techniques are mainly based on one of the following three types of mid-frequency vibro- acoustic modelling principles： （1） enhanced deterministic methods, （2） enhanced statistical methods, and （3） hybrid deterministic/statistical methods. It is shown that, although recent developments have led to a significant step forward in industrial applicability, mature and adequate prediction tech- niques, however, are still very much required for solving sound transmission through, and radiation from, extruded aluminium panels used on high-speed trains. Due to their great potentials for predicting mid-frequency vibro-acoustics of stiffened panel structures, two of recently developed mid-frequency modelling approaches, i.e. the so-called hybrid finite element-statistical energy analysis （FE-SEA） and hybrid wave-based method- statistical energy analysis （WBM-SEA）, are then recapitulated.

Characterization of energy and performance of swine fed a novel corn-soybean extruded product

Background： A novel extruded product was characterized with a metabolism and lactation trial to establish the product＇s energy content, and its effects on lactating sow performance. The product was composed of a 60：40 corn-soybean blend, which was then extruded. This product containing the co-extruded 60：40 corn-soybean blend was commercially developed and is used extensively in swine diets in southwest Minnesota. GE of dietary treatments were determined by isoperibol bomb calorimetry. Twelve barrows （59.9 ± 1.4 kg）, were used to determine the digestible and metabolizable energy of the extruded product. DE of treatments was determined by subtracting fecal energy from GE provided to barrows by each respective treatment. ME was determined by subtracting urinary energy from calculated digestible energy. Sixty-three sows were used for the lactation trial. Three dietary treatments were utilized： CONTROL （an industry standard diet）; PRODUCT （contained the product, vitamins and minerals）; OIL （matched the lysine：ME ratio of PRODUCT by addition of soy oil）. Sow weight, backfat thickness at the right and left last ribs, body condition score, number of piglets, and litter weights were recorded on the date of farrowing （d 0）, （d 9）, and at weaning. Blood and milk samples were obtained at weaning, and blood was analyzed for plasma urea nitrogen （PUN）, milk was analyzed for total protein and fat content. Results： On a dry-matter basis, the test diet provided 3,908 kcal/kg DE and 3,833 kcal/kg ME, which was significantly greater than the basal diet, which provided 3,633 kcal/kg DE and 3,567 kcal/kg ME （P 〈 0.0001）. These data were used to establish the DE and ME of the product, which were 3,882 kcal/kg and 3,798 kcal/kg, respectively, on an as-fed basis. No effect of diet was observed for changes in sow backfat （RBF P = 0.24; LBF P = 0.07） or body condition score （P = 0.12） during lactation. Milk total protein （P = 0.69）, fat （P = 0.66）, PUN, average piglet gain （P = 0.55） and piglet mortality （P = 0.70） did not differ between treatments. Conclusions： While the novel extruded product was higher in energy content than traditional feedstuffs, it resulted in the same lactational sow performance. Thus, the co-extruded corn-soybean product is a reasonable inclusion in sow lactation diets.

Formability evaluation of AZ31B extruded tube for hydroforming process

Hydroforming of magnesium and aluminum alloy tube at elevated temperature is becoming a very promising method to manufacture light-weight hollow components.Uniaxial tensile test and hydrobulging test were used to investigate the formability of AZ31B magnesium tube at different temperatures.The tube was manufactured by porthole die extrusion.Results show that as temperature increase,the tension formability along the extrusion direction measured by tensile test increases significantly,whereas the maximum hydrobulging ratio measured by hydrobulging test does not change accordingly.This anisotropy character of the tube,i.e.,different properties in axial direction and hoop direction,is mainly dependant on the extrusion process.In addition,there exists several weld lines along the extrusion direction.These weld lines will become the weakest positions when formed at elevated temperature,and will consequently decrease the formability of the tube during hydroforming process.

Experimental Study on Extruded Beer Adjunct Used for Brewing Beer

The properties of saccharified and boiled worts between extruded and traditional non-extruded beer adjuncts were studied at the laboratory and a small beer brewing equipment(100 L) in this paper. Test results indicate that the main saccharification indices and filtration speeds of worts between extruded and traditional non-extruded beer adjuncts are similar basically. The collected rate of extracted material of worts of extruded beer adjuncts is 8% more than that of traditional non-extruded beer adjuncts. Fermentation time of worts of extruded beer adjuncts is 10 % less than that of traditional non-extruded beer adjuncts. The energy consumption of extruded beer adjuncts in saccharification process is 13 % less than that of traditional non-extruded beer adjuncts.

Extruded Soybean Samples for Mechnical Oil Expression

Soybean is generally recognized as a source of edible and the deoiled meal is seen as a source of protein in animal feed.In recent years.However,more interest has been directed toward using soy meal as a protein souce for human consumption.Extrusion expelling of soybean provides an opportunity in this direction.The main focus of this study was to maximize the oil recovery from extruded soybean processed using three different kinds of extrudates and processing conditions.These extruded samples were later pressed uniaxially in a specifically designed test cell and the oil recovery was recorded over time.The effects of process variables,including applied pressure,pressing temperature and sample height,were investigated.Results indicated that over90% of the available oil could be recovered from pressing of extruded soy samples.The information generated is likedly to be useful in interpreting the effect of precess variables and extruding equipment for pretreatment of soybean for subsequent mechanical oil expression.

Influences of liners and magnetic flux concentrator on induced Joule heat in hot extruded billet

In the production of pipes by hot extrusion method,billets should be heated to a certain temperature before hot extrusion by induction heating. The segmented liners in the induction furnace can possibly affect the circumferential Joule heat generation,thus leading to an uneven temperature field. The commonly used magnetic flux concentrators （MFC） can increase the temperature on both ends of the billet. In this paper ,the possible effect of liners and the factors affecting the utilization of the MFC,including the permeability,dimension and position,are all numerically studied and determined.