磁粒研磨去除Al 7075交叉孔棱边毛刺的试验研究

目的探究磁粒研磨法对去除Al7075交叉孔棱边毛刺的影响,提高孔道的研磨质量及毛刺去除效率。方法首先,通过对圆柱型磁极进行轴向、径向开槽,并利用ANSOFT软件对磁极进行磁场模拟,分析三种不同形状的磁极的磁感应强度变化;其次,通过磁粒研磨法对交叉孔孔道内壁进行研磨,去除棱边毛刺;最后,测取交叉孔表面微观形貌、材料去除量、毛刺高度和表面粗糙度。结果研磨加工时间为10 min、磁极转速为1500 r/min的条件下,磁极为径向开槽时,材料去除量高达46 mg,孔道内壁的表面粗糙度由原始1.5μm降至0.5μm,孔道表面研磨效果较为理想,棱边毛刺完全去除;当磁极为非开槽时,材料去除量为40 mg,表面粗糙度下降至0.65μm,棱边毛刺几乎完全去除;磁极为轴向开槽时,表面粗糙度下降至0.8μm左右,材料去除量约为30 mg,剩余毛刺高度约为5μm。结论研磨时间为10 min,磁极转速为1500 r/min,当磁极径向开槽时,相对于轴向开槽磁极和不开槽磁极,磁粒研磨Al7075交叉孔内表面的效果更好,毛刺去除效率更高。     

磁粒研磨TC4孔棱边毛刺的机理及试验研究

目的探究磁粒研磨法去除TC4孔棱边毛刺的机理,寻求去除TC4孔棱边毛刺的最佳工艺方案。方法分别对磁极单轨迹运动、磁极复合轨迹运动下磁粒研磨去除孔棱边毛刺的基本原理进行分析,分别利用ANSOFT和ANSYS软件对孔棱边处的磁场强度和切削力进行模拟分析。通过磁粒研磨法对孔棱边毛刺进行研磨去除试验,利用超景深3D显微镜测取孔棱边毛刺的微观形貌以及毛刺的高度。结果磁极为单轨迹运动时,磁极自转转速为2000 r/min,研磨加工15 min后,TC4孔棱边的毛刺高度由原始的60μm左右降至5μm左右。磁极为复合轨迹运动时,磁极自转转速为2000 r/min,磁极公转速度为30 r/min,加工时间为12 min,TC4孔棱边的毛刺已经完全去除,且孔表面微观形貌较好。结论当磁极为复合轨迹运动时,相对于传统的磁极单轨迹运动,孔棱边毛刺的去除效率进一步提高,TC4孔表面微观形貌得到极大改善。     

复合磁极磁粒研磨平面机理及试验探究

目的 探究磁粒研磨中复合磁极磁回路对工件表面质量及表面粗糙度值的影响,解决传统平面磨粒受磁力较小而远离加工区域,从而使表面质量较低的问题.方法 对提出的磁极复合磁路法进行研磨机理分析,并通过磨粒在加工中的受力分析,进而分析影响因素.使用等效磁路法,对3种磁路所形成加工区域的磁感应强度进行计算,进而采用Ansoft Maxwell软件对3种磁路的磁场梯度模拟仿真进行对比分析,综合分析、评价影响因素的作用,为试验打下理论基础.最后使用表面粗糙度仪及超景深3D显微镜,对采用不同磁回路研磨前后的工件表面粗糙度值及表面质量进行测量与记录.结果 复合磁极磁路中的磁感应强度大于传统研磨加工,具有明显、对称的磁场梯度效果.与传统式研磨相对比,表面粗糙度值从0.10μm降至0.06μm,在表面粗糙度改善率上提升40％,工件表面研磨质量较好.结论 复合磁极式磁粒研磨工艺对工件表面的划痕、凹坑、斑点等达到了良好的去除效果,使工件表面平整并具有镜面效果,较传统研磨明显具有质量好、效率高的优点.     

基于异步旋转磁极的TC4薄板双面磁粒研磨工艺研究

目的 为提升传统磁粒研磨TC4薄板的加工效率,改善表面形貌,设计了相对磁极产生相对转速差的双面磁粒研磨装置。方法 基于两侧相对磁极的异步旋转,使两侧磁极产生相对转速差,进行磁性磨粒的受力和运动分析,对材料去除量进行计算分析。利用Maxwell软件,对不同的相对转速差进行磁场的模拟仿真,进而使用设计的双面磁粒研磨加工装置,对TC4薄板的双面进行研磨。最后,使用粗糙度仪和超景深3D电子显微镜,对研磨前后的工件表面进行观察分析。结果 对于磁极的同步旋转,即当两侧磁极转速为500 r/min时,正面表面粗糙度Ra的平均值从0.47 μm下降至0.2 μm,下降幅度为57%,反面表面粗糙度Ra的平均值从0.46 μm下降至0.21 μm,下降幅度为54%。对于磁极异步旋转,即磁极Ⅰ转速为500 r/min、磁极Ⅱ转速为600 r/min时,正面表面粗糙度Ra的平均值从0.47 μm下降至0.1 μm,下降幅度为78%,反面表面粗糙度Ra的平均值从0.48 μm下降至0.1 μm,下降幅度为79%,正面最大高度差的平均值从62.5 μm下降至10.4 μm,下降幅度为83%,反面最大高度差的平均值从63.2 μm下降至10.3 μm,下降幅度为84%,材料去除效率最高,表面质量得到有效改善。结论 采用异步旋转双面磁粒研磨的方式,可以有效促进磁性磨粒的翻滚运动,加速切削刃的更新。该装置加工时能够产生相对较高的磁感应强度,磁场梯度变化适中,有利于提升表面质量,修复工件表面的缺陷,大幅度提升了研磨的效率。     

基于无理数转速比的导磁轴套磁粒研磨试验

目的 解决大型导磁类零件内表面的精密研磨加工困难、加工效率低等问题。方法 采用旋转磁极方法对内表面进行磁粒研磨。工件由车床主轴驱动旋转,将磁极伸入工件内部,并在电机驱动旋转的同时,随着车床刀架往复进给,驱使磁极与工件内表面之间填充的磁性磨粒摩擦工件表面,完成对工件内表面的光整加工。利用ADAMS软件对有理数和无理数转速比下的研磨轨迹进行模拟,讨论不同转速比对研磨轨迹和工件表面质量的影响;采用响应面法将影响研磨的主要工艺参数(工件转速、磁极转速、磁性磨粒粒径)进行优化设计;通过研磨试验分析表面形貌和表面粗糙度数据,验证优化后工艺参数的可靠性。结果 采用响应面法分析可知,当工件转速为98 r/min、磁极转速为2 435 r/min、磁性磨粒粒径为190 μm、磁粒研磨加工时间为40 min时,工件的表面粗糙度从原始Ra 3.32 μm降至Ra 0.198 μm,表面粗糙度改善率(ΔRa)为94.04%。工件表面划痕、加工纹理等表面缺陷得到了有效去除,加工后工件表面更加光亮、均匀,大幅提高了工件的使用寿命。结论 当磁极与工件的转速比为无理数时,其研磨效果最好,研磨轨迹的干涉效果更好,单位面积内的交错次数更多,交织出的网状结构网格更均匀、致密,未加工区域面积更小。采用响应面法能够对试验结果进行优化参数数学建模设计,拟合出的最佳工艺参数组合可提高大型导磁材料轴套类零件的加工效率和表面质量。     

超声磁粒复合研磨对石英玻璃管内表面的光整研究

目的探究超声磁粒复合研磨对石英玻璃管内表面管研磨的可能性,分析有无辅助磁极及不同粒径的研磨粒子对内表面的影响。方法在石英玻璃管内表面添加辅助磁极并辅助超声磁粒复合研磨装置,加快磨粒的翻滚,提高抛光质量和效率。结果采用超声磁粒复合研磨装置,选用150、250、350μm三种粒径的研磨粒子分别进行研磨实验,研磨40 min后,150μm的研磨粒子表面粗糙度值从原始4.4μm下降到1.2μm,250μm的研磨粒子表面粗糙度值下降到0.2μm,350μm的研磨粒子表面粗糙度值下降到0.6μm。对比传统磁粒研磨装置与超声磁粒复合研磨装置,保持研磨粒子粒径为250μm,经40 min研磨,在传统磁粒研磨装置上未添加辅助磁极,石英玻璃管内表面粗糙度值从原始4.4μm下降到2.8μm;在传统磁粒研磨装置上添加辅助磁极,粗糙度值从原始4.4μm下降到1.1μm;在超声磁粒复合研磨装置上添加辅助磁极,粗糙度值从原始4.4μm下降到0.2μm。结论在石英玻璃管内表面添加辅助磁极后,表面粗糙度值得到下降。采用超声磁粒研磨装置使石英玻璃管内表面粗糙度值在原有基础上进一步下降,且选用粒径为250μm的研磨粒子最佳。加工后,工件内表面的加工均匀性显著提升,原始缺陷和原始波峰基本去除。     

瓦形磁极对磁粒研磨加工管件内表面的影响

目的 提高磁粒研磨加工厚壁管内表面的表面质量与表面粗糙度改善率.方法 采用聚磁盘与瓦形磁极相配合的方式,通过仿真软件对不同数量的瓦形磁极与聚磁盘的多种组合进行模拟仿真,并分析其磁感应强度变化与磁力线分布.利用磁粒研磨法对管件内表面进行研磨试验验证,研磨后对工件表面粗糙度进行测量,并观察工件表面微观形貌.分析瓦型磁极数量...     

旋转磁极在SUS304管内表面精密抛光中的应用

用传统磁力研磨方法对管内表面进行抛光处理时,加工效率低且加工后表面质量差。针对该问题,文章采用旋转磁极辅助磁力研磨装置,对SUS304管内表面进行抛光试验研究。分析了3种不同加工方式下工件内表面的表面质量、表面微观形貌以及材料去除量的变化。结果表明:添加旋转辅助磁极后管内表面上无"彗尾"划痕现象,经过40min的加工,工件内表面质量得到明显改善,表面粗糙度值由R_a1.3μm降至R_a0.2μm,加工效率显著提升,材料去除量可达到100mg。     

仿形组合磁极研磨增材制造复杂表面工艺研究

目的 改善零件表面质量,延长零部件使用寿命。方法 应用Ansys Maxwell模拟仿真沿盘形磁极圆周开不同形状槽时磁极磁感应强度的分布。以钛合金(Ti6Al4V)材料增材制造的成形零件为例,基于磁粒研磨抛光技术,利用仿形组合开槽磁极对成形零件沟槽表面进行研磨抛光。结果 模拟结果表明,沿磁极圆周开均布矩形槽时,磁极的磁感应强度波峰值最大,波谷值最小,磁场强度梯度变化最大,最适合复杂工件表面的磁粒研磨。磁性磨粒粒径、磁极转速和研磨间隙等参数的设置都会影响研磨加工效果,经模拟和实验获得最佳工艺参数为磁性磨粒粒径180 μm、磁极转速1 000 r/min、研磨间隙2 mm。设置如上所述的加工工艺参数,成形零件沟槽表面粗糙度Ra由原始的10.70 μm降为0.52 μm,且其表面缺陷得到有效去除。结论 采用仿形组合开槽磁极应用磁粒研磨技术能够实现增材制造复杂零件表面的研磨抛光。     

超声复合磁力研磨加工镍基合金GH4169异形管

为解决镍基合金GH4169异型管内壁难研磨及研磨不均匀问题,采用超声复合磁力研磨光整加工方法进行试验。分析在超声复合磁力研磨条件下,主轴转速、加工间隙、超声频率和超声振幅对异形管内壁表面质量的影响。结果表明：在超声轴向频率为19 kHz、振幅19 μm,主轴转速1000 r/min,磁性磨粒平均粒径250 μm,加工间隙2 mm加工条件下,加工30 min后,管件内壁表面粗糙度Ra由原始的2.4 μm降至0.31 μm。通过在管件内部添加圆柱形辅助磁极,使得内外两磁极形成闭合磁场回路,增加磁场力的作用。辅助磁极连接高频轴向超声振动,使得吸附在磁极上的磁性磨粒在旋转运动和轴向高频振动复合作用下划擦、研磨管件内表面。由于研磨轨迹发生交叉复杂化,使得异型管内壁研磨后的表面质量和表面粗糙度得到明显提高;管件内壁表面残余应力由拉应力+52 MPa转变为压应力-48 MPa,表面应力状态得到较好的改善。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.