工艺参数对玻璃钢传动轴粘接性能的影响

研究了粘接工艺过程中基材表面粗糙度、粘接温度、粘接湿度、胶层厚度、固化温度等因素对玻璃钢传动轴粘接部件粘接性能的影响,通过试验得到玻璃钢基材与金属部件粘接的最佳工艺参数。

钙钛矿包容核废物致密化工艺参数优化

探索采用自蔓延高温合成技术制备包容锶核素(Sr2+)的钙钛矿(CaTiO3)固化体,根据燃烧合成热力学计算反应的绝热燃烧温度Tad,分析SHS产物致密化的影响因素,通过实验确定了其工艺参数并进行优化,得到理想大废物固化体.

桑皮纤维的脱胶工艺研究

参考大麻纤维的脱胶工艺,研究了酸温度、酸浓度、碱浓度、煮练时间等对桑皮纤维脱胶效果的影响。结果表明:酸处理温度60℃、酸浓度2.5 g/L、碱浓度1.5 g/L、煮练时间为2 h时,脱胶的效果最佳。

电子束焊接参数对高温合金小熔深焊缝形貌的影响

通过选取电子束焊的主要焊接参数,采用正交试验方法研究了各参数对GH4169和GH600高温合金小熔深焊缝形貌的影响。结果表明,影响熔深的参数依次为电子束流、加速电压和焊接速度,影响熔宽的参数依次为加速电压、电子束流和焊接速度。当加速电压为100 k V、电子束流为4.0 m A、焊接速度为20mm·s^(-1)时,可满足零件设计图的熔深要求。同时解决了某型航空发动机电子束焊使铜合金封严层的钎焊缝出现熔蚀的问题。

Cross-section distortion and springback characteristics of double-cavity aluminum profile in force controlled stretch-bending

3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.

结晶器铜板上激光熔覆镍基合金

利用5kWCO2激光器在结晶器铜板上熔覆镍基合金，并研究了熔覆层组织性能．选用与结晶器铜板成分相近的镍基自熔合金粉末Nickel—base HMSP1015—00（Ni1015），利用等离子喷涂技术在铜板上预涂Ni1015合金，然后再采用高能量密度激光进行重熔．借助OM，SEM和显微硬度计分析测定了涂层的显微组织形貌、组织成分和截面显微硬度分布情况．所得到的熔覆层表面平整均匀，与基体为冶金结合；熔覆层平均显微硬度为270HV0．05，是基体的3．2倍（85HV0．05）．确定出本实验合适的激光熔覆工艺参数：功率密度为1．58×100kW／cm^2时，扫描速度为3～4m／min．

Optimization of AZ80 magnesium alloy squeeze cast process parameters using morphological matrix

The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33） orthogonal array of Taguchi method. In Taguchi method, a 3-level orthogonal array was used to determine the signal/noise ratio. Analysis of variance was used to determine the most significant process parameters affecting the mechanical properties. Mechanical properties such as ultimate tensile strength, elongation and hardness of the components were ascertained using multi variable linear regression analysis. Optimal squeeze cast process parameters were obtained.

High temperature deformation behavior and optimization of hot compression process parameters in TC11 titanium alloy with coarse lamellar original microstructure

The high temperature deformation behaviors of α＋β type titanium alloy TC11 （Ti-6.5Al-3.5Mo-1.5Zr-0.3Si） with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a＋fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α＋β phase field. The peak of efficiency of power dissipation in α＋β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α＋β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a＋β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results.

Effects of process parameters on mechanical properties and microstructures of creep aged 2124 aluminum alloy

A series of tests were carried microstructures of 2124 aluminum alloy in increase of aging time, temperature and low-to-peak-to-low manner. No significant out to investigate the effects of process parameters on mechanical properties and creep aging process. The results show that creep strain and creep rate increase with the applied stress. The hardness of specimen varies with aging time and stress in a effect of temperature on hardness of material is seen in the range of 185-195 ℃. The optimum mechanical properties are obtained at the conditions of （200 MPa, 185 ℃, 8 h） as the result of the coexistence of strengthening S＂ and S＇ phases in the matrix by transmission electron microscopy （TEM）. TEM observation shows that applied stress promotes the formation and growth of precioitates and no obvious stress orientation effect is observed in the matrix.

Variable-based Ramberg-Osgood constitutive model of power spinning bushing

The influences of power spinning process parameters on the mechanical properties of spinning parts were analyzed with an SXD100/3-CNC numerical control power spinning machine.The unidirectional tensile tests were carried out.Based on the experimental data,a ternary quadratic regression equation was established by orthogonal experiment.The Ramberg-Osgood constitutive model of tin-bronze connecting rod bushing was obtained.Referred to the constitutive relation of macroscopic incremental,the incremental elastoplastic constitutive relation of spinning parts was deduced based on the Mises yield criterion and kinematic hardening model.The results can be applied to the elastoplastic analysis in finite element numerical simulation.

Chemical etching process of copper electrode for bioelectrical impedance technology

In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.

Stochastic Analysis of Interconnect Delay in the Presence of Process Variations

Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect delay. The technique decouples the stochastic interconnect segments by an improved decoupling method. Combined with a polynomial chaos expression （PCE）, this paper applies the stochastic Galerkin method （SGM） to analyze the system response. A finite representation of interconnect delay is then obtained with the complex approximation method and the bisection method. Results from the analysis match well with those from SPICE. Moreover, the method shows good computational efficiency, as the running time is much less than the SPICE simulation＇s.

Effect of gelcasting conditions on quality of porous Al-Cu alloy

The porous A1-Cu alloy was prepared by the gelcasting process. And the effects of gelcasting conditions, such as monomer, the volume ratio of cross-linker and monomer, dispersant and redox initiating system on the height, gelling time and the quality of green body were investigated. （It was found that the dispersant and monomer played significant roles in the height and quality of green bodies, respectively.） The optimal conditions were 10% monomer, 2% cross-linker, 0.2% initiator （volume fraction）, and 1.2 g dispersant, in which the green body exhibited the best quality. The mechanisms of process conditions in eliminating the cracks and forming the pores of in the five stages were proposed. Mercury porosimetry provided a description of pore diameter ranging from 10 to 10000 nm and open porosity of 38.78 %.

Grain refinement of Mg-Al alloys by optimization of process parameters based on three-dimensional finite element modeling of roll casting

To study the influence of roll casting process parameters on temperature and thermal-stress fields for the AZ31 magnesium alloy sheets,three-dimensional geometric and 3D finite element models for roll casting were established based on the symmetry of roll casting by ANSYS software.Meshing method and smart-sizing algorithm were used to divide finite element mesh in ANSYS software.A series of researches on the temperature and stress distributions during solidification process with different process parameters were done by 3D finite element method.The temperatures of both the liquid-solid two-phase zone and liquid phase zone were elevated with increasing pouring temperature.With the heat transfer coefficient increasing,the two-phase region for liquid-solid becomes smaller.With the pouring temperature increasing and the increase of casting speed,the length of two-phase zone rises.The optimized of process parameters（casting speed 2 m/min,pouring temperature 640 ℃ and heat transfer coefficient 15 kW/（m2·℃） with the water pouring at roller exit was used to produce magnesium alloy AZ31 sheet,and equiaxed grains with the average grain size of 50 μm were achieved after roll casting.The simulation results give better understanding of the temperature variation in phase transformation zone and the formation mechanism of hot cracks in plates during roll casting and help to design the optimized process parameters of roll casting for Mg alloy.

Property of Dual-purposed Maca Powder as Medicine and Food

[Objective] The aim was to research property of maca and three plants＇ powders and process parameters of compound maca direct compression. [Method] Based on analysis data from SAS, bulk density, tap density, angle of repose and swelling of powders were studied as per single factor method and orthogonal exper- imental design. [Result] The test indicated that fillibilities of plant A and B, and maca powders are better and flowability plays an important role in fractional close of compound maca powder; plant A and B powders have a significant effect on bulk density of maca （P=0.0125）, an extremely significant effect on swelling volume ratio （P=0.008 9） and little effect on tap density （g/ml）; the optimal process condition of compound maca powder is as follows： A at 0.15 share; B at 0.10 share; C at 0.05 share; the optimal swelling volume ratio is at 2.459. [Conclusion] The technology is reasonable in formulation and satisfactory in fillibility, swelling ability, flowability, and it could serve as theoretical basis for the industrial production of maca tablets.

Effects of process parameters on microstructure and wear resistance of TiN coatings deposited on TC11 titanium alloy by electrospark deposition

In the present study,the effects of process parameters(output voltage x,nitrogen flux l and specific strengthening time s)on the microstructure and wear resistance properties of TiN coatings prepared by electrospark deposition(ESD)were investigatedsystematically.The microstructure of the coatings was characterized for thickness(TOC),content of TiN(CON)and porosity(POC).A statistical model was developed to identify the significant factors affecting the microstructure and wear resistance of the coatings.The results show that the output voltage x and nitrogen flux l present significant effects on majority of the evaluation indexes such asTOC,friction coefficient(COF)and wear mass loss(Id),while the specific strengthening time s has a significant effect on POC and asmall effect on the other indexes.The optimal process parameters were obtained as follows:output voltage(x,60V),nitrogen flux(l,15L/min)and specific strengthening time(s,3min/cm2).The variation of wear mass loss(Id)by the variation of the outputvoltage(x)and nitrogen flux(l)is attributed to the change of wear mechanisms of TiN coatings.The main wear mechanism of TiNcoating prepared under optimal process parameters is micro-cutting wear accompanied by micro-fracture wear.

Significance-based optimization of processing parameters for thin-walled aluminum alloy tube NC bending with small bending radius

Thin-walled aluminum alloy tube numerical control （NC） bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element （FE） simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC bending d50 mm×1 mm×75 mm and d70 mm×1.5 mm×105 mm （initial tube outside diameter D0 × initial tube wall thickness t0 × bending radius R）, and qualified tubes are produced.

Process forces and heat input as function of process parameters in AA5083 friction stir welds

AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.

Prediction and optimization of process parameter of friction stir welded AA5083-H111 aluminum alloy using response surface methodology

A systematic approach was presented to develop the empirical model for predicting the ultimate tensile strength of AA5083-H111 aluminum alloy which is widely used in ship building industry by incorporating friction stir welding(FSW) process parameters such as tool rotational speed,welding speed,and axial force.FSW was carried out considering three-factor five-level central composite rotatable design with full replications technique.Response surface methodology(RSM) was applied to developing linear regression model for establishing the relationship between the FSW process parameters and ultimate tensile strength.Analysis of variance(ANOVA) technique was used to check the adequacy of the developed model.The FSW process parameters were also optimized using response surface methodology(RSM) to maximize the ultimate tensile strength.The joint welded at a tool rotational speed of 1 000 r/min,a welding speed of 69 mm/min and an axial force of 1.33 t exhibits higher tensile strength compared with other joints.

Influences of diffusion bonding process parameters on bond characteristics of Mg-Cu dissimilar joints

In many circumstances,dissimilar metals have to be bonded together and the resulting joint interfaces must typically sustain mechanical and/or electrical forces without failure,which is not possible by fusion welding processes.The melting points of magnesium(Mg)and copper(Cu)have a significant difference(nearly 400℃)and this may lead to a large difference in the microstructure and joint performance of Mg-Cu joints.However,diffusion bonding can be used to join these alloys without much difficulty.This work analyses the effect of parameters on diffusion layer thickness,hardness and strength of magnesium-copper dissimilar joints.The experiments were conducted using three-factor,five-level,central composite rotatable design matrix.Empirical relationships were developed to predict diffusion layer thickness,hardness and strength using response surface methodology.It is found that bonding temperature has predominant effect on bond characteristics.Joints fabricated at a bonding temperature of 450℃, bonding pressure of 12 MPa and bonding time of 30 min exhibited maximum shear strength and bonding strength of 66 and 81 MPa, respectively.