高强韧锌基耐磨合金组织与性能

在ＺＡ２７合金的基础上，通过合金元素的调整和优化，研制了一种具有优良力学性能和耐磨性能的锌基耐磨合金。本文着重分析了该合金的组织形成和具有高强韧综合性能的原因。     

Achieving Superior Strength and Ductility of AlSi10Mg Alloy Fabricated by Selective Laser Melting with Large Laser Power and High Scanning Speed

AlSi10Mg alloy was prepared by selected laser melting(SLM) in a high laser power range 300–400 W. The effects of energy density on the relative density, microstructure and mechanical properties of the SLMed AlSi10Mg alloy were studied. The results showed that the SLMed AlSi10Mg alloy fabricated at a laser power of 400 W and a scanning speed of 1800 mm/s had a relative density of 99.4%, a hardness of 147.8 HV, a tensile strength of 471.3 MPa, a yield strength of 307.1 MPa, and an elongation of 9....     

新型改性高强高韧铝合金的组织和性能

在6061合金的基础上添加混合稀土,设计出一种新的Al-Mg-Si系合金(6061-RE合金)。合金经熔炼和挤压加工后进行淬火、人工时效处理,并利用金相显微镜、扫描电镜及电子万能实验机对合金微观组织和力学性能进行检测分析。结果表明,添加稀土后,铝合金的晶粒得到细化,晶界有少量稀土相析出。添加0.3wt%混合稀土试样的抗拉强度最高,达到了342MPa,其伸长率为11.5%。抗拉强度和伸长率都得到了改善,硬度也有所下降,呈现出良好的力学性能。     

多向强应变及时效处理对铝合金的强韧性影响

利用多向锻造及时效处理技术加工变形铝合金,使铝合具有高强度和良好的塑性.研究结果表明,试样组织显著细化且超细的第二相微粒弥散分布,抗拉强度和硬度大幅度增加且塑性良好,抗拉强度和伸长率分别为396.3 MPa和11.08％.锻件强度和硬度大幅度提高是由于组织显著细化且超细的第二相微粒弥散分布;多次累积应变和时效处理改善晶界状态,使锻件的塑性增强.     

新型高强韧Ti-Al-Fe-B系钛合金组织和性能研究

研究了Al元素(1%～3%,质量分数)的添加及热处理工艺对合金Ti-x Al-3.5Fe-0.1B组织和力学性能的影响。结果表明:Ti-x Al-3.5Fe-0.1B为α+β两相钛合金,随着Al含量由1%增加到3%,合金屈服强度由590 MPa提高到900 MPa,抗拉强度由808 MPa提高到1074 MPa,固溶强化明显,同时,延伸率达到15.4%。组织观察发现:随着Al含量的增加,片层状初生α相片层厚度减小,合金组织细化明显。另一方面,对Ti-3Al-3.5Fe-0.1B合金进行不同的热处理发现:双重退火后,合金的屈服强度进一步提高到1000 MPa,抗拉强度提高到1144 MPa,同时,塑性也提高到17.5%,合金具有优异的强韧匹配性。这主要是因为合金双重退火过程中,组织中生成的亚稳β相分解生成次生α相,次生α相尺寸小,位错在次生α相边界受阻。同时,次生α相在β基体上弥散分布,形成弥散强化,导致合金强度进一步提高。另一方面,组织中等轴α相的存在,对于塑性的提高起到了积极的作用。     

高强韧A357合金凝固组织及热处理工艺的研究

采用新砂型改善了合金的凝固组织，通过正交试验及单项热处理试验，考察了固溶处理参数及时效处理参数对合金力学性能的影响，提出了合金的最佳热处理工艺方案，使合金达到了高强高韧的目的     

压铸高强韧Al-Cu系合金的组织性能及热处理探讨

为了弥补目前压铸铝合金强韧性不足，进行了高强韧Al-Cu系合金的压铸及热处理的试探性研究．在ZL201的基础上．添加合金化元素B、Zr、V等．改善合金的铸造性能，进行压铸成形试验。试验研究发现压铸大大细化了合金的微观组织．铸态性能较金属型高，再经低温时效后合金强度达到一般高强压铸铝合金的水平．但塑性较之提高20％以上。     

Obtaining Ultra-High Strength and Ductility in a Mg–Gd–Er–Zn–Zr Alloy via Extrusion,Pre-deformation and Two-Stage Aging

The Mg–12Gd–1Er–1Zn–0.9 Zr(wt%) alloy with ultra-high strength and ductility was developed via hot extrusion combined with pre-deformation and two-stage aging treatment.The age-hardening behavior and microstructure evolution were investigated.Pre-deformation introduced a large number of dislocations,resulting in strain hardening and higher precipitation strengthening in the subsequent two-stage aging.As a result,the alloy showed a superior strength–ductility balance with a yield strength of 506 MPa,an ultimate tensile strength of 549 MPa and an elongation of 8.2% at room temperature.The finer and denser β' precipitates significantly enhanced the strength,and the bimodal structure,small β-Mg_5RE phase as well as dense γ' precipitates ensured the good ductility of the alloy.It is suggested that the combination of pre-deformation and two-stage aging treatment is an eff ective method to further improve the mechanical properties of wrought Mg alloys.     

阳极氧化对AZ31镁合金表面粘接性能的影响

为了提高AZ31镁合金表面与有机涂料和胶粘剂的粘接强度,通过对镁合金表面进行阳极氧化处理的方法,利用正交试验对镁合金硅酸盐阳极氧化电解液配方和工艺进行了优化,研究了其对氧化膜粘接性能的影响.得出不同工艺参数对粘接强度的影响程度从小到大排列为:KF浓度＜Na2B4O7浓度＜KOH浓度＜阳极氧化时间＜电流密度.所得氧化膜的表面电位比基体提高了200mV,粘接强度提高了约50%.结果表明:氧化膜的表面形貌对粘接强度起决定性影响,表面成分则影响不大.     

高强韧性变形铝合金的制备

铝合金是应用广泛的金属材料,但铝合金的强度不高,这在很大程度上限制了铝合金的应用范围.本研究利用多向锻造及时效处理技术加工变形铝合金.结果表明,试样组织显著细化且超细的第二相微粒弥散分布,抗拉强度和硬度大幅度增加且塑性良好,抗拉强度、硬度和伸长率分别为386.1 MPa、120 HV和11.02％;强度和硬度大幅度提高是由于组织显著细化和超细第二相微粒弥散分布；多次累积应变和时效处理能改善晶界状态,使锻件塑性增强.     

非晶态合金的强韧性及其研究进展

从强度、硬度、塑性、韧性及脆性等方面综述了非晶态合金的强韧性及其研究进展,简要讨论了目前存在的问题及今后的发展趋势.     

Room Temperature Ductility and Microstructure of Magnesium AZ31B Sheet

Formability of wrought magnesium alloys at room temperature or slightly elevated temperatures is modest, reaching about 20% elongation in a tension test and exhibiting poor resistance to strain localization and failure. The hexagonal close packed structure of Mg has few active slip systems at lower forming temperatures, limiting ductility and reducing applications in auto body structures. Much greater levels of ductility can be reached at higher temperatures (typically >300 °C), but this is expensive and inconvenient for a high-volume production environment. Tension testing and biaxial forming of annealed AZ31B magnesium alloy sheets were done at room temperature to various levels of strain. High-resolution electron back scatter diffraction (EBSD) was used to measure twin fraction and dislocation density, in order to find relationships between strain and potential failure locations within the microstructure. Twin fractions were found to have a weak positive correlation to uniaxial and biaxial tensile strain, while dislocation density was found to correlate more strongly with uniaxial tensile strain.     

冷却强度及变形程度对挤压AZ31镁合金组织性能的影响

选择AZ31镁合金为原材料,在400℃下挤压散热片型材,就冷却强度及变形程度对制品的性能(抗拉强度和导电率)及组织结构的影响进行研究。结果显示:挤压温度为400℃,制品经水冷却,变形程度大的型材具有更高的抗拉强度和导电率。     

AZ系镁合金研究现状

介绍了在AZ系镁合金中添加常见稀土元素(RE)的工艺,并对其超塑性、表面处理技术以及板材成形技术等的研究现状进行了综述。最后就该合金的发展前景进行了展望,认为镁合金在今后工程实践中将发挥更加重要的作用。     

高强高韧合成球墨铸铁的组织及力学性能

以废钢为主要原材料(20%生铁+20%回炉料+60%废钢),使用中频感应电炉熔炼,采用中间加入和镜面加入联合增碳方式,制备了合成球墨铸铁QT450-23铸件。合成铸铁球化级别1级,球化率95%,石墨圆整,球径10～20μm,基体为100%铁素体。合成铸铁抗拉强度为450MPa,伸长率为23.3%。在高温组织中,奥氏体枝晶发达,显著提高材料的冲击韧性,V型缺口冲击试样常温冲击韧性为18.4 J/cm2,是相同成分和工艺条件下,传统生铁为主配方球铁的2倍。     

Influence of Mechanical Fibering on Anisotropy of Strength and Ductility

The effects of non-crystallographic fibering resulting from mechanical working are discussed in terms of the anisotropy of fracture mode, and are related to significant microstructural details.     

5083铝合金的类超塑性行为

研究了冷轧退火状态下Al Mg系5083合金的高温形变行为。结果表明,合金在较宽的温度区间及应变速率范围内显示出高的伸长率。合金在形变过程中,晶粒发生细化。机理研究表明,高伸长率并不是超塑性变形的结果,而是溶质原子拖拽或粘性流动控制蠕变的结果。     

Corrosion behaviour of silicon-carbide-particle reinforced AZ92 magnesium alloy

The corrosion behaviour of silicon-carbide-particle (SiCp) reinforced AZ92 magnesium alloy manufactured by a powder metallurgy process was evaluated in 3.5 wt.% NaCl solution, neutral salt fog (ASTM B 117) and high relative humidity (98% RH, 50 °C) environments. The findings revealed severe corrosion of AZ92/SiC/0-10p materials in salt fog environment with formation of corrosion products consisting of Mg(OH)₂ and (Mg,Al)_x(OH)_y. The addition of SiCp increased the corrosion rate and promoted cracking and spalling of the corrosion layer for increasing exposure times. Composite materials revealed higher corrosion resistance in high humidity atmosphere with almost no influence of SiCp on the corrosion behaviour.     

含有不同尺度微裂纹的铝合金伸长率模型

基于铝合金在变形过程中形成不同尺度的微裂纹,建立了铝合金伸长率与微米级的结晶相及沿晶界分布的亚微米级的弥散相的非线性解析模型,模型的预测与试验值较为符合。借助模型的理论分析,可以定量地得出不同尺度的结晶相,弥散相含量及尺寸对铝合金伸长率的影响。同时,根据模型的解析结果,提出了改善铝合金伸长率的方法。     

高强韧Al-Si(A357)合金的晶粒细化研究

对高强韧Al-Si(A357)合金晶粒细化技术进行了研究.结果表明:采用Ti,B复合细化时,细化效果比单一Ti,B,Zr细化效果更好,随B量增加,同时细化效果明显改善.采用Ti,B,Zr复合细化时,当Ti/B=1,0.2时,Zr促进晶粒细化:当Ti/B=5时,Zr却阻碍晶粒细化.Al-5Ti-1B细化剂对Al-Si合金具有良好的细化效果.对于Al-Si合金而言,最佳的工艺为720℃加入4%的细化剂,保温5～10 min.