汽车用6111铝合金板材力学性能和织构研究

对6111铝合金板材T4P态(预时效后室温放置)和烤漆态(185℃×20 min)沿不同方向的力学性能和织构差异进行研究,结果表明:合金两个状态沿不同方向的力学性能存在明显差异,屈服强度沿轧向最高,分别为171MPa和261MPa,烘烤增量达90 MPa,而伸长率却在与轧向呈45°方向最高;T4P态r和n值均沿轧向最高,而与轧向呈45°方向最低;合金T4P态已完全再结晶,表层晶粒尺寸小于中间层,纵截面再结晶晶粒长宽比高于横截面的;合金板材滑厚度方向存在明显的织构梯度,表层以{001} 〈100〉 Cube织构和β取向线上的{114} 〈131〉织构为主,而中间层除{001} 〈100〉 Cube织构外,还存在旋转立方织构{001} 〈310〉;据此建立了6111铝合金板材不同状态力学性能和织构之间的定量关系.     

终轧工艺对AM50镁合金轧板力学性能和织构特征的影响

采用不同的轧辊温度和速率制备AM50镁合金轧板,研究终轧工艺对镁板力学性能和织构特征的影响。研究表明：在轧辊温度为200°C和轧辊速率为5 m/min条件下制备的镁板的强度（极限抗拉强度：295 MPa;屈服强度：224 MPa）和伸长率（22.9%）之间达到较优组合;在热轧过程中,轧板的屈服强度主要取决于轧制温度,而织构强度则对轧辊速率更为敏感;提高轧制温度或轧辊速率均可改善AM50镁合金板材力学性能的各性异性。     

Reverse bending effect on the texture, structure, and mechanical properties of sheet copper

The effect of reverse room-temperature bending on the crystallographic texture, metallographic structure, and mechanical properties of preliminarily rolled and annealed sheets of copper has been studied. It has been found that the type of the initial structure and the texture represented by the {001}??100?? recrystallization orientation, remains of the deformation texture {112}??111??, and twin orientations do not change; only the ratio of these orientations changes in the process of the reverse bending, which naturally leads to changes in the mechanical properties.     

Effects of the rotary embossing process on mechanical properties in aluminum alloy 1050 sheet

Heat shields are designed to protect components from heat damage, and one method of producing heat shields is with the embossing process. The embossing process is a sheet metal-forming method that is utilised in strengthening sheet metals. This method also increases the surface area useful for heat transfer. In this paper, the effect of this technique on the yield load, tensile load, bending strength and buckling strength for different sheet thicknesses of aluminium alloy 1050 sheets is investigated. Furthermore, the efficacy of this forming technique as a method for strengthening the sheets is discussed.     

轧制工艺对AZ31B镁合金薄板组织与性能的影响

研究了轧制温度和轧制速度对AZ31B镁合金薄板微观组织演变和力学性能的影响。结果表明,轧辊加热有利于镁合金薄板成型;AZ31B镁合金在低温或低速轧制时薄板纵向组织为大量的切变带,切变带区域包含大量孪晶组织,横向组织为含极少量孪晶的等轴晶组织;在轧制温度为400℃和轧制速度为16m/min轧制时,由于动态再结晶,横纵截面组织均为等轴晶。AZ31镁合金薄板的最佳轧制制度为轧辊温度为70℃、轧制温度为400℃、轧制速度为6m/min,此工艺轧制的薄板横向抗拉强度、屈服强度和伸长率分别为350MPa、300MPa和12%,纵向为345MPa、290MPa和11.2%,纵向与横向性能差别明显减小。     

包覆叠轧TA7钛合金薄板的组织与力学性能

为了解决TA7钛合金板材冷加工困难的状况,对TA7钛合金薄板采用包覆叠轧工艺进行热轧直接成品轧制,可以有效简化工艺、降低成本。分析两种不同加工工艺下板材的组织、织构与性能。结果表明:采用包覆叠轧工艺可以使TA7钛合金板材获得较好的组织,具备较好的综合力学性能。     

工艺参数对板料成形性能的影响

传统上，人们对于工艺参数对板料成形性能的影响的认识只是定性的。利用板料成形的计算机数值模拟技术，可以定量地考察各种工艺参数对板料成形性能的影响。     

A study on the boss forming process of AZ31 Mg alloy sheet

A series of boss forming tests has been carried out using an AZ31 Mg alloy sheet at 250 °C, 300 °C, and 350 °C with various lubrication conditions to obtain optimum process conditions. The Mg alloy sheet had a homogeneous distribution of very fine sized grains. Surface defects generated during boss forming process could be reduced by changing the friction conditions, as prescribed by FEM analysis using the DEFORM 2D program. The modified boss forming process, lubricating only on the front side, was found to be successful in manufacturing the boss without defects.     

6111铝合金板材加工过程中织构的演变

用取向分布函数法研究了6111铝合金板材生产加工过程中织构的演变,结果表明,热轧后,(-αAl基体表现为较弱的铜型轧制织构,经退火后变为随机织构。将退火板材冷轧成薄板后形成了较强的铜型轧制织构,在随后的固溶处理时发生再结晶,并形成主要由Cube ND15和{011}<111>两个组分构成的再结晶织构。     

轧制工艺对TC4合金板材织构演变及组织性能的影响

本文研究了顺向冷轧和换向冷轧两种轧制方式对TC4板材显微组织、织构和力学性能的影响规律。研究结果表明：两种轧制工艺的晶粒都有所细化;顺向冷轧微观组织仍存在带状组织,α晶粒呈现出方向性的拉长;换向冷轧晶粒破碎的更加均匀,退火后形成的细小等轴α晶粒。换向冷轧工艺的塑性指标显著优于顺向冷轧,强度指标略低于顺向冷轧,但是板材的RD和TD之间的差值明显减少。原始冷轧板材主要存在(-12-10)<10-10>棱锥型织构,强度较高;顺向冷轧遗传了原始板材的织构组分;换向轧制促进(0001)的强基面织构向ND-TD面和RD-TD面发生漫射,并存在一定角度的偏转,有效降低棱锥型织构强度,促进织构组分重新分配,显著改善板材的各向异性。     

The effect of substrate composition on the electrochemical and mechanical properties of PEO coatings on Mg alloys

Plasma electrolytic oxidation (PEO) is a unique surface treatment technology which is based on anodic oxidation forming ceramic oxide coatings on the surface of light alloys such as Mg, Al and Ti. In the present study, PEO coatings prepared on AZ91D, AZ31B, AM60B and AM50B Mg alloys have been investigated. Surface morphology and elemental composition of coatings were determined using scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). SEM results showed that the coating exhibited a porous top surface layer and a subsequent dense layer with micro-pores and shrinkage cracks. Phase analysis of coatings was carried out by X-ray diffraction (XRD). XRD analyses indicated that PEO coatings on AZ alloys had higher amount of Periclase (MgO) followed by the presence of Spinel (MgAl₂O₄) e.g. on the AZ91D alloy compared to that on AM series alloys. In order to examine the effect of substrate composition on adhesion strength of PEO coating scratch tests were carried out. Electrochemical corrosion tests were undertaken by means of potentiodynamic polarization technique in 3.5% NaCl solution at room temperature (20 ± 2 °C). Corrosion test results indicated that the corrosion rates of coated Mg alloys decreased by nearly two orders of magnitude as compared to bare Mg alloys. PEO coatings on AZ series alloys showed better corrosion resistance and higher adhesion properties than AM series alloys. In addition to the PEO processing parameters, such are mainly attributes of the compositional variations of the substrate alloys which are responsible for the formation, phase contents and structural properties of the PEO coatings.     

工艺参数对蠕变时效2124铝合金力学性能和微观组织的影响

研究2124铝合金在蠕变时效过程中工艺参数对力学性能和微观组织的影响。结果表明，蠕变量和蠕变速率随着时效时间、温度、应力的增大而增大。硬度随着时间和应力的增加呈类似于先增加后减小的趋势。在实验温度185～195℃范围内，温度对硬度的影响不大。当蠕变条件为200MPa、185℃、8h时，试样得到最佳的力学性能，此时试样基体内同时存在强化相S＂相和S＇相。透射电镜观察表明外加应力能促进析出相的析出和长大，基体中没有发现明显的应力位向效应。     

热处理参数对5052铝合金板材力学性能的影响

以5052-H32铝合金冷轧板为研究对象,借助于单向拉伸试验、硬度测试对不同热处理参数条件下的力学性能进行研究,分析不同热处理工艺参数对5052铝合金力学性能参数的影响机制,结果表明:对5052-H32铝合金进行再次热处理时,可以显著地降低其变形抗力,提高塑性变形能力;在热处理过程中的加热温度起主要作用,在合理的热处理...     

镁合金板材的固体颗粒介质拉深工艺参数

提出基于固体颗粒介质成形(SGMF)工艺的镁合金板材差温拉深工艺,并展开试验研究。通过对AZ31B镁合金薄板进行差温拉深成形试验,研究了成形温度、拉深速度、压边力、压边间隙、凹模圆角和润滑条件对拉深性能的影响,确定AZ31B镁合金板料最佳成形工艺参数。结果表明:该工艺可显著提高镁合金板材的成形性能,成形温度及拉深速度对板料拉深性能影响较大,板料最佳成形温度区间为290～310℃,颗粒介质与板料理想温差为110～150℃;压边力和压边间隙对拉深性能产生联合影响;此外,凹模圆角和润滑条件也对拉深性能有一定的影响。当上述工艺参数达到最佳值时成功拉深出极限拉深比(LDR)为2.41的工件。     

工艺参数对铝锂合金搅拌摩擦焊搭接接头力学性能的影响

通过对铝锂合金搅拌摩擦焊搭接接头组织与力学性能测试,分析了不同焊接工艺参数对搭接接头拉伸性能的影响.结果表明,搅拌针的长度对接头性能影响最大,搅拌针长度从2.8 mm变为2.5 mm时,所有接头强度和塑性均有明显增加.旋转频率/焊接速度(η)对接头性能也有影响,随着η小幅度增加,接头的强度和塑性都有一定提高.在旋转频率为800 r/min、焊接速度为200 mm/min(η=4)条件下,接头的强塑性最佳,抗拉强度达到467 MPa,为母材的94％,断后伸长率为3.18％.从断口形貌观察发现,拉伸试样从前进侧搭接界面的“钩状”位置起裂,沿热影响区扩展至母材发生断裂.     

工艺参数对2195铝锂合金搅拌摩擦焊接头力学性能的影响

文中采用不同搅拌摩擦焊工艺对2195铝锂合金的可焊性进行了研究.结果表明,接头抗拉强度随旋转频率的提高先增后减,随焊接速度的提高先增后减.当旋转频率为600 r/min、焊接速度为200 mm/min时,接头抗拉强度最高,为432.8 MPa,是母材强度的77.3%.接头区域的硬度低于母材.热影响区内临近HAZ/TMAZ界面的区域是整个接头中软化程度最大的区域.根据热输入的变化,断裂方式可以分为两种:模式1:断裂发生在热影响区,呈现塑性断裂特征,断口特征为等轴韧窝;模式2:断裂发生在焊核区,断裂方式为韧-脆混合型断裂.     

镁合金板材颗粒介质拉深工艺参数数值模拟

为提高镁合金板材拉深性能,提出一种基于固体颗粒介质成形(Solid granules medium forming,SGMF)工艺的镁合金板材差温拉深工艺。以单向拉伸试验获取的AZ31B镁合金板材真应力—应变曲线和颗粒材料性能试验构建的介质线性Drucker-Prager本构模型为基础,采用有限元法对板材拉深成形进行热力耦合数值模拟并进行试验验证,研究压边力、压边间隙和温度对板材拉深性能的影响。结果表明:压边间隙和压边力联合控制比单纯控制压边力或是压边间隙更能有效地提高板材拉深性能;AZ31B镁合金板材在拉深过程中对温度有较强敏感性,板材变形温度为250~300℃,颗粒介质与其温差100~150℃时,板材达到最佳拉深性能;颗粒介质能够对工件筒壁部位提供轴向摩擦力,该摩擦力能有效提高材料拉深性能并保证板厚的均匀性,这是SGMF工艺的优势所在。     

Ca对AZ81镁合金高温性能的影响

通过合金制备、微观分析和力学性能测试等方法研究了碱土元素Ca对AZ81镁合金微观组织和力学性能的影响。结果表明,加入适量碱土元素Ca后使AZ81镁合金的组织明显细化,β（Mg17Al12）相减少,并析出粒状的化合物Al4Ca。经固溶时效处理后,随着碱土元素含量增加。在室温、150℃和175℃三个温度下。合金的强度和延伸率基本上呈先升后降的趋势。当Ca含量为1％时,合金的室温强度和150℃强度同时达到最大值。分别为224．462MPa和183．542MPa。在各温度下对应的延伸率分别是9．2％和11．34％。