Al-5.87Zn-2.07Mg-2.42Cu合金形变热处理过程的组织与性能演变

通过维氏硬度试验、力学性能试验以及透射电镜观察,研究了Al-5.87Zn-2.07Mg-2.42Cu合金在最终形变热处理(固溶—预时效—变形—终时效)过程中的组织演变和力学性能,并优化出最适宜的工艺制度。结果表明,Al-5.87Zn-2.07Mg-2.42Cu合金最适宜的形变热处理工艺为480℃/1 h+100℃/8 h+30%+120℃/10 h。100℃/8 h预时效处理后,合金基体内弥散析出大量细小的沉淀相。经30%冷变形引入位错后进行120℃/10 h终时效处理,析出相数量增多且尺寸增大。最终形变热处理后合金的硬度、抗拉强度和屈服强度分别为200 HV、645 MPa和621MPa,分别比T6态合金的增加了19 HV、67 MPa和110 MPa。     

时效工艺对Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金性能的影响

Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金自然时效的速度慢,且不稳定,故一般不在自然时效状态下应用.为了获得更高的强度、较好的抗蚀性、较低的疲劳裂纹扩展速度以及性能的稳定,该系合金一般采用人工时效处理.热处理工艺参数主要包括固溶处理温度、固溶处理时间、时效温度、时效时间.本实验研究了时效工艺对Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金性能的影响,旨在摸索Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金的合理热处理工艺.     

时效对新型Al-Zn-Mg-Cu合金力学及应力腐蚀性能的影响

通过力学性能和电导率测试、慢应变速率试验(SSRT)以及显微组织TEM分析,研究了不同时效制度对新型Al-7.5Zn-1.7Mg-1.4Cu-0.12Zr合金力学及应力腐蚀性能的影响。结果表明,合金的力学性能和应力腐蚀性能与时效制度密切相关。T6状态下,晶内析出相弥散细小,晶界析出相呈连续分布,合金的强度最高,抗应力腐蚀性能最差;经T7双级过时效处理后,晶界析出相粗化呈离散分布,出现明显宽化的晶间无析出带,合金的抗应力腐蚀性能得到明显提高,但其强度损失较多。经三级时效处理后,合金的组织综合了T6态和T7态的优点,使合金既有高的强度又有良好的抗应力腐蚀性能,合金的极限抗拉强度、屈服强度、伸长率和电导率分别达到580,570 MPa,16.7%和23.3 MS.m-1。     

时效处理对Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr合金超声铸锭轧件组织与抗腐蚀性能的影响

分别采用T6、T73和RRA 3种时效制度对超声铸造Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr铝合金热轧板进行时效处理,研究时效制度对材料的组织、力学性能与耐腐蚀性能的影响,并与未经超声熔体处理的合金热轧板进行对比。结果表明:对于超声铸造Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr铝合金的热轧板,与T6时效态合金相比,T73时效态合金的抗腐蚀性能较好,但强度显著降低,RRA状态的合金强度与T6态合金相当,抗腐蚀性能显著提高;相对于未经超声熔体处理的合金,在超声波的空化、声流和机械振动效应的作用下,铸态合金的合金元素固溶度以及基体空位浓度都增加,在其组织遗传效应的影响下,采用相同时效工艺处理后合金中析出相的分布更加均匀但出现部分粗化现象,均匀分布的细小析出相对合金的强度有积极影响,粗化的析出相对合金的强度不利,但能提高合金的耐腐蚀性能。     

一种高硬度铸造镁合金

设计了一种成分(质量分数/%)为Mg-8Zn-6Al-3Cu-3Ca-1.5Mn-1Si的合金,利用金相显微镜、扫描电镜、X射线衍射和维氏硬度计研究了自然冷却、快速冷却及时效处理对合金显微组织和硬度的影响.Mg-8Zn-6Al-3Cu-3Ca-1.5Mn-1Si合金慢冷组织主要由α-Mg、Mg2Cu6Al5、CaMgSi、Mg2Zn3等相构成,没有出现Mg17Al12相.合金经快冷后,抑制了第二相从基体中的析出;时效10 h后,CaMgSi相以细小的块状相均匀析出.合金具有较高的硬度值,在时效时间10 h时最大HV值达到111.     

双级时效对Mg-2.8Nd-0.4Zn-0.5Zr合金微观组织和力学性能的影响

采用OM、SEM、TEM以及硬度测试和拉伸力学性能测试等手段,研究了双级时效对Mg-2.8Nd-0.4Zn-0.5Zr合金显微组织和力学性能的影响。结果表明,合金经260℃/30 min+200℃/4 h双级时效处理后,其抗拉强度和屈服强度较200℃/14 h单级时效合金分别提高23 MPa和20 MPa,并且达到硬度峰值所需时间缩短9.5 h。主要是由于第一级高温预时效过程中析出β1相,在第二级时效过程中,β1相保留,同时又析出β″相,并且β″相尺寸较单级时效后的合金更细小。在两种析出相同时作用的情况下,其强化效果明显优于单一β″相强化的单级时效处理。     

添加微量锆、铒对铸造Al-8.25Zn-2.4Mg-2.3Cu合金组织与力学性能的影响

采用光学显微镜、扫描电镜和X射线衍射等方法研究了微量Er和压元素对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织的细化作用及其细化机制,同时考察了微合金化元素对试验合金力学性能的影响.结果表明:单独添加Zr对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织有一定的细化作用,而复合添加Zr和Er则对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织产生强烈的细化效果,分析表明其细化效应与合金凝固过程中Al8Cu4Er相、Al3Er相和Al3Zr等复合质点的析出及微量元素在凝固界面前沿的富集有关.经过T6处理,Al-8.25Zn-2.4Mg-2.3Cu-0.18Zr-0.40E哈金的抗拉强度σb为600 MPa;延伸率达到8%.与7075合金相比,试验合金的强度与塑性均获得大幅度提高.     

固溶温度对挤压态Mg-13Al-6Zn-4Cu合金组织与性能的影响

采用不同的固溶温度对挤压态Mg-13Al-6Zn-4Cu(质量分数,%)合金进行热处理,然后在(150℃/10 h)条件下进行时效处理,通过金相显微镜、扫描电镜及能谱分析、维氏硬度与极化曲线测试,研究固溶温度对挤压态合金显微组织、硬度与腐蚀性能的影响。结果表明:固溶处理促进晶界处的β-Mg_(17)Al_(12)相充分溶入α-Mg基体中。提高固溶温度使基体晶粒再结晶长大,逐渐缩小T-MgAlCuZn相心部的Cu元素富集区,改变β析出相的形态和分布,促进层片状β相在α-Mg晶界析出,从而提高时效态合金的硬度。但固溶温度超过420℃时,合金晶粒粗化并发生过烧。固溶温度升高导致合金腐蚀电位负移,腐蚀电流增大,腐蚀速率加快。     

固溶处理对新型Al-8.8Zn-2.3Mg-1.8Cu-0.13Zr合金挤压材组织及性能的影响

采用金相、扫描电镜、能谱分析、拉伸性能等分析检测方法研究了一种新型Al-8.8Zn-2.3Mg-1.8Cu-0.13Zr合金型材热处理过程的组织与性能演变。结果表明,挤压态试验合金中主要有α(Al)、(AlCuZn)_2Mg、MgZn_2相,(AlCuZn)_2Mg发生相转变的起始温度为476.9℃,且随固溶温度的提高,第二相回溶充分,再结晶比例逐渐增加;470℃~480℃固溶并时效后合金的强度较高,但480℃时发生轻度过烧,塑性下降;合金较适宜的固溶温度为470℃~475℃。     

双级时效制度对7150铝合金微观组织和性能的影响

采用拉伸测试、电导率测试和透射电镜等手段研究了双级时效制度对7150铝合金的力学性能、电导率和微观组织的影响。结果表明:在本研究范围内,第一级时效制度对合金的力学性能和电导率影响不大;合金经过120℃/8h+160℃/6h,可以达到与单级峰时效处理相当的抗拉强度,并且电导率有明显提高;第二级时效温度为168℃时效时,相比在160℃进行第二级时效,合金在具有同等电导率水平时,损失的强度相对较多,但时效时间明显变短;120℃/8h+160℃/32h双级时效后,合金的抗拉强度为560MPa,屈服强度为520MPa,延伸率为11.5%,电导率22.7MS.m-1,晶内沉淀析出相以η′和η为主,晶界析出相完全断开。     

含锶钪2099型铝锂合金的晶间腐蚀和剥落腐蚀性能

采用维氏硬度计(HV)、金相显微镜(OM)和扫描电镜(SEM)显微分析技术,研究了一种锶钪复合微合金化2099型铝锂合金(其化学成分为:Al-2.57Cu-1.86Li-1.31Zn-0.420Mg-0.321Mn-0.0735Zr-0.0943Sr-0.0433Sc)的晶间腐蚀性能和剥落腐蚀性能。结果表明,该合金经均匀化退火处理(475℃×24 h)、热锻压变形加工处理(三次变形量均约为100%)、固溶处理(540℃×2 h)、冷水淬火(水温大约5℃)、T8时效处理(121℃×14 h+151℃×48 h)后,合金显微硬度值达到174.6 HV,比2024-T6合金(固溶处理500℃×2 h+时效处理191℃×12 h)高23.1%。合金具有良好的抗晶间腐蚀性能和抗剥落腐蚀性能,其抗腐蚀性能明显优于2024-T6合金。该合金Sr,Zr,Sc的复合微合金化作用(细化粗大第二相、抑制再结晶和晶粒长大),第二相分散、分布不连续,以及Zn的含量高,是合金抗腐蚀性能高的主要原因。研究结果还说明了微量复合添加对铝锂合金具有奇效微合金化作用的过渡族金属元素Sr,Sc,是得到抗腐蚀性能良好的铝锂合金的一种有效途径。     

Microstructures and Properties of Al-Zn-Mg-Cu-Zr Alloys with Minor Scandium

The microstructures of Al-Zn-Mg-Cu-Zr al- loys with minor Sc were studied by using optical microscope（OM）, scanning electron microscope （SEM） and transmission electron microscope（TEM）. The tensile mechanical properties and electric conductivity of the studied alloys under different treatment conditions were tested. The results show that adding minor Sc can greatly fines the grain size of the Al-Zn-Mg-Cu-Zr alloy ingots and obviously improves the tensile properties and electric conductivity of the alloys. The strengthening mechanism is considered as fine grain strengthening, sub-structure strengthening and dispersion strengthening by Al3 （Sc, Zr）.     

Nd对Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响

研究稀土Nd对均匀化态Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响.通过真空感应熔炼制备镁锂合金铸锭, 经均匀化处理(280 ℃, 24 h)得到均匀化态Mg-11Li-3Al-2Zn-xNd-0.2Zr(x=0, 0.5, 1.0, 1.5)合金.采用XRD和SEM分析合金的显微组织, 并对合金进行拉伸试验和断口分析.采用电化学法和析氢失重法研究合金在3.5 %NaCl溶液中的腐蚀行为.结果表明:Mg-11Li-3Al-2Zn-0.2Zr合金主要含有β-Li、AlLi、MgLi₂Al相, Nd的加入使合金中形成NdAl3相.随着Nd含量的增加, 合金的强度和塑性呈先增大后降低的趋势. Mg-11Li-3Al-2Zn-1Nd-0.2Zr合金表现出较优的力学性能, 其抗拉强度和延伸率相对于Mg-11Li-3Al-2Zn-0.2Zr合金分别提高了28.8 %和51.3 %.稀土Nd的添加使合金的耐蚀性能提高.      

Microstructure and mechanical behavior of spray-deposited High-Li Al-Li alloys

High-Li alloys, with the composition Al-3.8Li-XCu-1.0Mg-0.4Ge-0.2Zr, were synthesized using a spray deposition technique (wt. pct, X=0∼1.5). The microstructure of the spray-deposited Al-Li alloys consisted of equiaxed grains with an average grain size in the range from 20 to 50 μm. The grain-boundary phases were fine and discrete. The spray-deposited and thermomechanically processed materials were isothermally heat treated at 150 °C and 170 °C to investigate the age-hardening kinetics. It was noted that the spray-deposited Al-3.8Li-XCu-1.0Mg-0.4Ge-0.2Zr alloys exhibited relatively sluggish aging behavior. The peak-aged condition was achieved at 170 °C in the range from 20 to 90 hours. It was noted that Cu increases the hardness of alloys during aging. Moreover, the influence of Cu on age-hardening kinetics is marginal. The mechanical properties of the spray-deposited and extruded Al-Li alloys were studied in the underaged, peak-aged, and overaged conditions. For example, the peak-aged yield strength, tensile strength, and ductility of Al-3.8Li-1.0Cu-1.0Mg-0.4Ge-0.2Zr are 455 MPa, 601 MPa, and 3.1 pct, respectively. Moreover, an increase in the Cu content of the alloy led to improvements in strength, with only slight changes in ductility, for Cu contents up to 1.0 wt pct. Beyond this range, an increase in Cu content led to decreases in both strength and ductility.     

Preparation,microstructure and properties of Al-Zn-Mg-Sc alloy tubes

The Al-6.0Zn-2.0Mg-0.2Sc-0.10Zr hollow tube ingots, prepared by semi-continuous casting technology, were subjected to ho- mogenization treatment, hot extrusion, intermediate annealing, tension, solution and aging treatment. The microstructures and properties of as-cast Al-Zn-Mg-Sc alloy at different homogenization treatment conditions were studied using hardness measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. The results showed th...     

新型铝合金阳极在NaOH碱性溶液中的腐蚀行为

制备了两种不同含量的Al-Ga-In-Zb-Mg-Mn合金和Al-Ga-In-Sn-Zn-Mg-Mn合金，共三种新型铝合金阳极材料。研究了该系列合金在4mol／LNaOH碱性溶液中的自腐蚀速率和电化学性能。结果表明：在不同的电解液中铝阳极表现出不同的自腐蚀速率和不同的电极电位；合金元素的均匀分布可极大地降低铝阳极的自腐蚀速率。研制出的新型铝合金阳极材料具有优良的电化学性能和良好的耐腐蚀性能，No．1、No．1-1和N0．3阳极在80℃、电流密度为800mA／cm^2条件下、在添加偏铝酸盐时的电解液中，其稳态平均电位分别达到了-1．576V、-1．574V和-1．53V（vs．Hg／HgO）；同时铝合金阳极具有良好的铸造性能和机加工性能。     

Effect of processing and heat treatment on behavior of Cu-Cr-Zr alloys to railway contact wire

A new series of Cu-Cr-Zr alloys to be used as railway contact wire, Cu-0.26 wt pct Cr-0.15 wt pct Zr, Cu-0.13 wt pct Cr-0.41 wt pct Zr, and Cu-0.34 wt pct Cr-0.41 wt pct Zr, were studied. The results indicated that processing and aging treatment had an effect on the microstructure, tensile strength, and electrical conductivity behavior of the Cu-Cr-Zr alloys. Process I (solution treatment + cold work + aging) was superior to process II (cold work + solution treatment + aging), because precipitation can occur heterogeneously at the dislocations and subcells. An appropriate processing and aging treatment may improve the properties of the alloys due to the formation of fine, dispersive, and coherent precipitates within the matrix. It is demonstrated that the best combination of tensile strength and electrical conducitivity, on the order of 599 MPa and 82 pct IACS (International Annealed Copper Standard), respectively, can be obtained in alloy Cu-0.34 wt pct Cr-0.41 wt pct Zr in the solution-heat-treated, cold-worked, and aged condition. The mechanism of tensile and conductive properties of Cu-Cr-Zr alloy is also discussed.     

Effects of yttrium on recrystallization and grain growth of Mg-4.9Zn-0.7Zr alloy

Recrystallization and grain growth in Mg-4.9Zn-0.7Zr and Mg-4.9Zn-0.9Y-0.7Zr alloys as a function of temperature on deformation were investigated with regards to hot rolling and annealing. The influence of yttrium addition on the microstructure was examined by X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The results indicated that yttrium addition promoted nucleation of recrystallization during hot rolling process. The grain size of Mg-4.9Zn-0.7Zr alloy samples grew significantly with annealing temperature （300-400 ℃） and holding time （0-120 min）, while the microstructure of the alloy with yttrium addition remained unchanged and fine. The activation energy of grain boundary migration for Mg-4.9Zn-0.9Y-0.7Zr alloy samples （56.34 kJ/mol） was higher than that for Mg-4.9Zn-0.7Zr （42.66 kJ/mol） owing to the pinning effect of Y-containing particles. The proposed growth models of recrysta/lized grains for the two studied alloys conformed well to E. Robert＇s grain-growth equation. Besides, the ultimate strength and yield strength of the alloys with yttrium addition were improved with good plasticity.     

含银Al-4.5Zn-1.0Mg-0.5Cu合金的强化固溶行为

采用拉伸力学性能测试、金相显微观察、扫描电镜及透射电镜等分析手段,研究了Al-4.5Zn-1.0Mg-0.5Cu-0.4Ag合金的强化固溶行为。结果表明:经强化固溶处理后,合金固溶态的抗拉强度和屈服强度以及伸长率分别较常规固溶的低15 MPa、16 MPa和1.7%;峰值时效态的抗拉强度和屈服强度较常规固溶的分别高62 MPa和68 MPa,伸长率低0.8%。;强化固溶可使Al-4.5Zn-1.0Mg-0.5Cu-0.4Ag合金固溶后的第二相粒子减少,但使其时效后的强化相数量增多,密度增大。