虚拟样机技术在高功率激光器制造信息集成中的应用

在对比分析传统设计模式与现代设计模式设计活动的基础上,结合制造信息化现状,提出将虚拟样机技术应用于高功率激光器的设计,给出了基于虚拟样机的高功率激光器设计过程中CAD／CAM／CAE制造信息集成的方法。     

残余应力对X80 UOE钢管耐电化学腐蚀性能的影响

采用极化曲线测试和交流阻抗分析研究了不同残余应力状态下X80 UOE管线钢母材和焊缝在NS4模拟土壤溶液中的电化学腐蚀行为。结果表明,残余拉应力的存在造成局部自腐蚀电位的降低,为应力腐蚀裂纹的产生起到加速作用;X80 UOE钢管的焊缝较母材更易发生腐蚀;但残余应力对X80 UOE钢管母材应力腐蚀行为的影响更大;高残余拉应力试样的表面膜层的阻抗最小,更容易发生局部溶解腐蚀破坏。     

亚晶及析出相强化对Al-Zn-Mg-Cu合金性能的影响

采用金相显微镜、XRD物相分析、透射电镜观察和力学性能测试,研究了真空感应熔炼水冷铜模铸造下Al-8.2Zn-2.05Mg(10Zn-2.5Mg,12Zn-3Mg)-2.2Cu-0.1Mn-0.25Zr合金析出相的强化效应,以及第1种合金在形变热处理工艺下引入的亚晶强化效应.结果表明,3种合金在T6(120℃时效24 h)状态下均析出了均匀弥散的强化相η’,此时析出相强化起主导作用.随着Zn、Mg含量的提高,析出强化相的数量逐渐增多,析出相强化效应增大,3种合金的抗拉强度分别为646.2、697.4和732.5MPa,伸长率分别为13.0％、10.6％和7.1％,抗拉强度与其析出相强化效应对应;采用120℃预时效12 h+120℃温变形30％+120℃终时效10 h的形变热处理工艺可使Al-8.2Zn-2.05Mg-2.2Cu-0.1Mn-0.25Zr合金获得亚晶组织,此时合金为亚晶强化与析出相强化共同作用的强化机制,合金的抗拉强度达到752.3MPa,伸长率为6.7％;亚晶内析出均匀弥散强化相提高合金性能,比单一增加析出相数量效果更好.     

Ti(C,N)对Ni基高温合金组织结构、力学性能和抗氧化性的影响

采用粉末冶金法制备Ni-20Cr-4Mo-0.15C和Ni-20Cr-4Mo-0.15C-12.85TiC-3TiN(质量分数,%)两种合金,研究Ti(C,N)质点引入对Ni基高温合金组织结构、力学性能和800℃抗氧化性的影响。结果表明,经1280℃真空烧结1h后,因12.85%TiC和3%TiN引入形成的Ti(C,N)质点,弥散分布于奥氏体基体的晶内和晶界处,使奥氏体基体晶粒明显细化,合金的密度从8.38g/cm3降至7.59g/cm3,维氏硬度从1850MPa升至3430MPa,抗拉强度从752MPa升至1192MPa。此外,合金在800℃空气中仍具有较好的抗氧化性,形成的氧化膜主要由α-Cr2O3和TiO2组成。     

超声波对7050铝合金组织和时效特性的影响

研究了超声波对铸造7050铝合金的微观组织和时效特性的影响.结果表明,与常规铸造比较,经超声处理的合金具有更加细小的微观组织,且更快达到时效峰值.超声处理7050合金在120℃、时效处理8h后,其强度即可达到峰值,抗拉强度、屈服强度和伸长率分别为602 MPa、547MPa和12.7％.而常规铸造合金,时效处理12 h后,其抗拉强度、屈服强度和伸长率达到峰值,分别为536MPa,462MPa和15.0％.     

Microstructure and Properties of SAE 2205 Stainless Steel After Salt Bath Nitrocarburizing at 450 °C

Nitrocarburizing of the type SAE 2205 duplex stainless steel was conducted at 450 °C, using a type of salt bath chemical surface treatment, and the microstructure and properties of the nitrided surface were systematically researched. Experimental results revealed that a modified layer transformed on the surface of samples with the thickness ranging from 3 to 28 μm changed with the treatment time. After 2205 duplex stainless steel was subjected to salt bath nitriding at 450 °C for time less than 8 h, the preexisting ferrite zone in the surface transformed into austenite by active nitrogen diffusion. The main phase of the nitrided layer was the expanded austenite. When the treatment time was extended to 16 h, the preexisting ferrite zone in the expanded austenite was decomposed and transformed partially into ε-nitride precipitate. When the treatment time extended to 40 h, the preexisting ferrite zone in the expanded austenite was transformed into ε-nitride and CrN precipitate. Further, a large amount of nitride precipitated from preexisting austenite zone. The nitrided layer depth thickness changed intensively with the increasing nitriding time. The growth of the nitride layer takes place mainly by nitrogen diffusion according to the expected parabolic rate law. The salt bath nitriding can effectively improve the surface hardness. The maximum values measured from the treated surface are observed to be approximately 1400 HV_0.1 after 8 h, which is about 3.5 times as hard as the untreated material (396 HV_0.1). Low-temperature nitriding can improve the erosion/corrosion resistance. After nitriding for 4 h, the sample has the best corrosion resistance.     

贵州省铝工业现状及未来发展方向

贵州铝土矿资源、能源及水源极为丰富,具备发展铝工业得天独厚的条件。经过半世纪的探索、实践及发展,贵州铝工业已成为国内铝行业重要基地。与此同时,贵州省铝工业快速的发展也存在一些问题。本文通过对贵州省铝企业和行业的调研,客观阐述了贵州省铝工业发展现状、存在问题及优势,并对贵州铝工业未来发展方向作了思考。     

沉积时间对镁合金表面Ca-P生物涂层耐蚀性能的影响

目的：镁合金在生物医学领域具有很好的应用前景,为消除其在人体环境中降解速度过快的不足,需在镁合金表面制备一层能够降低其腐蚀速度且具有很好生物相容性的防护涂层。方法采用电沉积法在AZ91D镁合金表面制备Ca-P生物涂层,沉积条件为：在Ca(NO3)2和NH4H2PO4浓度分别为0.1 mol/L和0.06 mol/L的电解液中,pH值4.5,沉积电压2 V,沉积时间分别为1、2、3和4 h。采用XRD、SEM/EDS分析Ca-P涂层的相结构、微观形貌和化学成分,测试Ca-P涂层在Hank,s模拟体液中的极化曲线。结果镁基体表面均获得物相为 DCPD(二水合磷酸氢钙)的生物涂层,但涂层表面形貌随沉积时间的不同变化明显,当沉积时间为3 h时,涂层颗粒尺寸均匀、细小,涂层钙磷比为1.324。极化曲线结果表明,沉积1 h时涂层对基体已有一定的防护作用,随着沉积时间的加长,涂层的腐蚀电压也呈增大趋势。相对镁基体,沉积3 h的涂层腐蚀电位升高了180 mV,腐蚀电流密度降低了3个数量级。结论当沉积时间为3 h时,涂层的耐蚀性最好。     

Novel Fe‐based complex oxide catalysts for hydroxylation of phenol

Novel catalysts for the hydroxylation of phenol, Fe–Si–O, Fe–Mg–O and Fe–Mg–Si–O complex oxides, have been synthesized by a coprecipitation method. X‐ray diffraction studies show that MgFe₂O₄ crystallites with spinel structure are formed in Fe–Mg–Si–O and Fe–Mg–O complex oxides and the crystallite size of the metal oxide or complex oxide is reduced after addition of Si. In the hydroxylation of phenol with hydrogen peroxide, Fe‐based complex oxides exhibit high activities after a short induction period. The phenol conversion is improved when silicon is introduced into the Fe‐based complex oxides, and formation of MgFe₂O₄ crystals with spinel structure in the catalysts increases the diphenol selectivity. The addition of a little acetic acid to the reaction liquid can shorten the induction period effectively. Under the same reaction conditions, phenol conversion and diphenol selectivity over the Fe–Mg–Si–O catalyst are close to those over TS‐1, and furthermore, the reaction time is more than ten times shorter as compared to TS‐1. The reaction mechanism of the hydroxylation of phenol on the catalysts has been studied, and a free‐radical mechanism initiated by the formation of phenoxy free radicals is suggested. This revised version was published online in August 2006 with corrections to the Cover Date.