新型耐磨球墨铸铁的研究

通过系统地研究以合金元素锰、辅加微量合金元素,取代贵重金属镍、钼、铜,采用不同于等温淬火的冷却方式,获得以针状组织（贝氏体＋马氏体）为主,有一定量奥氏体的新型耐磨球铁。冲击韧度可达9.8J/cm{sup}2以上,硬度可达55HRC。在磨球生产上应用结果表明,耐磨性比中锰球铁磨球提高一倍,冲击疲劳性能比中锰磨球提高7倍,而生产成本与之相当。     

外差干涉比相技术在纳米测量中的应用

利用塞曼激光和光波比相技术的结合实现了一种高精度激光外差干涉测量系统。它也可以用来直接测量空气折射率n。多次实验证实,dn/n的重复性为5×10{sup}-8。     

圆管进口段层流一湍流边界层发展区的流动阻力

本文提供了一种计算模型,可以根据前文[1][13]所提供的圆管进口段边界层单纯层流和单纯湍流时的近似分析解作为基础,计算3×10{sup}3≤ReD≤1×10{sup}5时进口平滑的圆管进口段内边界层先层流、然后过渡为湍流的任何区段不可压缩流体的流动阻力和壁面摩擦阻力。计算的流动阻力为文献[6]所报导的实验原始资料所验证。     

铸态铝黄铜的超塑性

本文 研究了未经任何预处理的大晶粒铸态铝黄铜（ZHA166-6-3-2）的超塑性,结果表明：在变形温度为520～585℃,初始应变速率为2.6×10-4～6.6×10-3s-1范围内,超塑拉伸的伸长率可达到120%以上,最佳应变速率为2.6×10-3s-1,变形温度为575℃,最大伸长率为230%,应变速率敏感性指数为0.32,金相组织分析表明：超薄变形主要发生在大晶粒内部,超塑变形促进亚晶的形成和动态再结晶的进行。     

文氏管及振动设备的气蚀腐蚀试验结果比较

本文对五种金属材料在振动（不流动）和文氏管（流动）的系统中用自来水作试验的气蚀腐蚀性能作了详尽的比较,不但研究了温度变化（27到93℃）、文氏管喉部流速（34到49米/秒）及振动器双振幅的影响,而且探讨了最大腐蚀速度MDPR max和气蚀孕育期IP与材料的布氏硬度BHN和极限变形能UR（=UTS{sup}2/2E）等机械性能之间的关系。在“腐蚀阻抗”MDPR max{sup}-1和IP与这些机械性能的关系上只获得中等地成功。但是,发现了一个适用于两种设备的MDPR max和IP间的令人满意的关系,其形式是MDPR max{sup}-1＝a×（IP）{sup}n,这里n接近于1（0.94）。由MDPR max量度的气蚀强度在振动设备中要大10到20倍,与振动器的振幅和材料有关。如果对各别的材料分别考虑的话,此数值在5到30之间变化,其中变化最大的是碳钢1018,而最小的是不锈钢316。这表明了在这些气蚀方式间形式上的重大差别,亦表明了对这两种设备中测得的数据进行的比较尚有不精确的地方。     

应变硬化和应变速率敏感材料在单向拉伸状态的塑性分析

对于即具有应变速率敏感,又具有应变强化效应的材料在单向应力拉伸的塑性流动及失稳分析,本文证明了Hart的分析的基础相同于Hutchinson等基于流动方程b＝Kε{sup}nε{sup}m的分析。然后,以Hart的分析为出发点,对Hart提出的流动稳定性及其判据（及JHC判据）给予讨论。表明Hart的流动稳定性判据适用于力学缺陷,并主要地依赖于应变硬化指数。在Hart的分析基础上,考虑到初始几何缺陷2（0）,对失稳过程给予增量分析和积分分析。增量分析给出了m和δ之间的（及n≠0的）简明关系：δ＝（1/α （0））{sup}m－1,δ＝（1/α （0））{sup}me{sup}n－1,积分分析得到了和Hutchinson等及Ghosh的“非线性长波分析”得到的积分关系在n＝0的情况下相同的结果。将这些关系和实验结果比较,吻合是好的。此外,对载荷的分析给出了恒定十字头速度L及恒定应变速度ε的载荷表达式。     

Cr12MoV钢表面磁控溅射TiB2-TiN薄膜的摩擦磨损性能

采用磁控溅射技术在淬火态Cr12MoV表面制备SiC/TiN、SiC/TiB2-TiN薄膜(SiC为中间层),研究TiN、TiB2-TiN薄膜的组织结构和摩擦磨损性能。结果表明,SiC薄膜与基材和TiN、TiB2-TiN薄膜间都具有明显的且呈梯度的元素扩散,界面结合良好。在水润滑条件下与钢球对摩时(载荷0.5 N,时间0.5 h),TiN薄膜、TiB2-TiN薄膜具有良好摩擦磨损性能,其平均摩擦因数分别为0.33、0.31,低于淬火态Cr12MoV的0.45,磨损速率分别为2.0×10-8和1.5×10-8mm3/(N.m),低于淬火态Cr12MoV的8.66×10-7mm3/(N.m),其中在水润滑条件下TiB2-TiN薄膜比TiN薄膜具有更好的摩擦磨损性能。     

Bi-2223/Ag超导带材的热压工艺及其变形机理研究

开发了制备Bi系高温超导带材的热压新工艺并研究了其变形机理。研究表明：合理的工艺参数为750℃/200 Mpa/30 min。Bi-2223带材经热压处理后能有效地提高粉芯的密度,可在较小的压力下获得较大的变形率,并且晶粒破碎程度较轻。带材经热压处理后的临界电流密度J c在77K和零场下最高达225MA/m{sup}2。     

汽车金属带－行星齿轮无级变速传动系统同步点振动控制研究

在对原有系统结构加以改进和同步点速比变化率实施控制的基础上,建立了传动系统于混合无级变速、同步点转换和纯无级变速三种工况下的键合图仿真方程。仿真结果表明：新系统于同步点对车体的冲击度远小于标准规定的10m/s{sup}3。     

应变速率对铸态低镍奥氏体不锈钢热塑性的影响

通过高温拉伸试验研究了应变速率对Cr15Mn9Cu2NiN和Cr17Mn6Ni4Cu2N两种铸态奥氏体不锈钢热塑性的影响。结果表明:Cr15Mn9Cu2NiN钢的显微组织为单一奥氏体,而Cr17Mn6Ni4Cu2N钢中有残留δ铁素体分布在奥氏体晶界和晶粒内部;将应变速率由0.1s-1升高至10s-1后,变形时奥氏体晶界处增加的应力集中的作用与减少晶界滑移的作用相抵消,因此对Cr15Mn9Cu2NiN钢的热塑性无明显影响;但Cr17Mn6Ni4Cu2N钢的显微组织中存在较多的奥氏体/铁素体相界,这些相界在高应变速率时会变成位错源迅速产生大量的位错,从而提高奥氏体和铁素体强度,降低铁素体处的应力集中作用,使其断面收缩率提高10%以上。     

锰基高强度高塑性高阻尼形状记忆合金研究

用磁悬浮熔炼、测定试样形状记忆效应（SME）、金相法、DSC、断口SEM和自由震动波衰减曲线等研究了高强度高塑性高阻尼的Mn基形状记忆合金的记忆特性,Cu、Ni、Fe、Cr、Ti、N等合金元素的作用。结果表明,Cu溶入愈多,合金的形状记忆效愈高;适当的时效热处理强化合金,提高SME;含Ti、N元素的合金Mn3有最好的SME,回复率达73％。所研究的合金都有明显的双程形状记忆效应,合金Mn3的双程形状记忆效应达21％,比较少见。淬火状态的合金有高的塑性,延伸率达25％,表示有极高的加工工艺性并有良好的阻尼抗震能力。淬火时效状态的合金有高的强度极限,尤其是高的屈服极限（σs=320—475MPa）,适当的塑性（δ=4．2—5％以上）,预示合金有较高的断裂韧性K1c,断裂前会有明显变形预示,提高构件工作安全性。合金元素还能提高所研究合金的抗氧化和抗腐蚀能力。     

Effect of Micro-scale Y Addition on the Fracture Properties of Al–Cu–Mn Alloy

Rare earth (RE) elements have positive effects on Al alloy, while most research is focused on microstructure and mechanical properties. As important application indices, toughness and plasticity are properties that are sensitive to alloy fracture characteristics, and few research studies have characterized the fracture properties of Al–Cu–Mn alloy on RE elements. The effect of different contents of Y on the fracture properties of Al–Cu–Mn alloy is investigated. T6 heat treatment (solid solution and artificial aging treatment), optical microscope (OM), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) methods are applied to the alloy. Results showed that when Y element is present at 0.1%, the section of the as-cast alloy has smaller sized dimples and the fracture mode presents ductile features. Slight changes in hardness are also observed and maintained at about 60 HV. With increasing content of the RE element Y from 0.1 to 0.5%, the θ phase and Cu atoms in the matrix were reduced and most stopped at Grain boundaries (GBs). Micro-segregation and an enriched zone of Y near the GBs gradually increased. At the same time, the inter-metallic compound AlCuY is aggregated at grain junctions causing deterioration of the micro-structure and fracture properties of the alloy. After T6 treatment, the flatness of the fracture surface was lower than that of all the as-cast alloy showing lots of dimples and teared edges with a significant increase in hardness. When Y content was 0.1%, the strength and hardness of the alloy increased due to refinement of the grain strengthening effect. The content of Y elements segregated in the inter-dendritic zone and GBs is reduced. Plasticity and deformation compatibility also improved, making cracks difficult to form and merge with each other along adjacent grain junctions and providing an increased potential for ductile fracture. This paper proposes the addition of RE Y as an effective and prospective strategy to improve the fracture properties of the Al–Cu–Mn alloy and provide a meaningful reference in terms of improving overall performance.     

面向21世纪的曲轴新材料

对发动机曲轴材料作了综合介绍。根据它的发展历史以及对各种种材料的化学成分、组织、性能、加工工艺、成本价格的比较分析,说明其发展趋势是以球铁曲轴替代锻钢曲轴,以铸态珠光体球铁曲轴替代热处理曲轴。球铁代钢的关键是提高韧性,自行研制的ＱＴ７４０－３铸态珠光体球铁曲轴表明,铸态球铁性能达到了一个新高新。另外对几种曲轴新材料进行了分析。     

Dry Sliding Friction and Wear Properties of Al–25Zn–3Cu–(0–5)Si Alloys in the As-Cast and Heat-Treated Conditions

Dry sliding friction and wear properties of ternary Al–25Zn–3Cu and quaternary Al–25Zn–3Cu–(1–5)Si alloys were investigated using a pin-on-disc test machine after examining their microstructures and mechanical properties. An alloy (Al–25Zn–3Cu–3Si), which exhibited the highest tensile and compressive strengths, was subjected to T7 heat treatment. Surface and subsurface of the wear samples were investigated using scanning electron microscopy (SEM). The hardness and both tensile and compressive strengths of the alloys increased with increasing silicon content, but the trend reversed for the latter ones above 3% Si. It was observed that T7 heat treatment reduced the hardness and both tensile and compressive strengths of the Al–25Zn–3Cu–3Si alloy, but increased its elongation to fracture greatly. Three distinct regions were observed underneath the surface of the wear samples of the Al–25Zn–3Cu–3Si alloy. The formation of these regions was related to the heavy deformation of surface material and mixing, oxidation and smearing of wear material. Al–25Zn-based ternary and quaternary alloys in both as-cast and heat-treated conditions were found to be superior to SAE 660 bronze as far as their mechanical and dry sliding wear properties are concerned.     

Sliding wear of cast zinc-based alloy bearings under static and dynamic loading conditions

The lubricated wear behaviour of cast journal bearings, produced from a series of zinc-based alloys and SAE 660 bronze as a reference material, was investigated under both static and dynamic loading conditions using a bearing test rig. All of the zinc-based alloys had higher wear resistance than the SAE 660 bronze. Among the zinc-based alloys, the wear resistance of the monotectoid-based alloys was superior to those based on near-eutectoid composition, and the best wear performance under both static and dynamic loading conditions was obtained with ZnAl40Cu2Si1 alloy. Copper content affected the wear resistance of monotectoid zinc-based alloys. Under dynamic loading conditions, it increased with increasing copper content up to 2%, but declined thereafter. Tensile properties and hardness of the monotectoid alloys were also affected by their copper content. Loading conditions had a strong influence on the wear rate. Under static loading conditions, as-cast zinc-based alloys showed higher wear resistance than the equivalent heat-treated alloys, but this behaviour was reversed for dynamic loading. Possible reasons for this are briefly discussed.     

厚壁复合钢板锥体热成形后冷却速度对组织和性能的影响

Q345R＋022Cr19Ni10（94＋4）复合钢板锥体在1030℃加热成形,950℃终止成形后覆层喷水,基层空冷,其基层力学性能试验-20℃冲击韧性不合格,金相检查为网状分布的多边形铁素体＋岛状组织和少量珠光体,晶粒度为9级。重新加热至成形温度浸水冷却,并在700℃回火,获得回火贝氏体组织,结果冲击韧性大幅提高,满足标准和设计要求。     

钙和锶对Mg_2Si/AZ91D复合材料组织和性能的影响

将铝-硅合金加入到AZ91D镁合金中,制备了原位合成Mg2Si/AZ91D复合材料,并研究了添加钙和锶对于复合材料铸态组织和力学性能的影响。结果表明:硅的加入在AZ91D镁合金中生成了高熔点、高硬度的Mg2Si强化相,但尺寸较大;元素钙和锶的综合作用可以显著细化复合材料基体的铸态组织,同时还可以明显改善Mg2Si的形态和分布,提高复合材料的强度。     

合金元素对室温油分级等温淬火贝氏体球铁组织和性能的影响

采用一种新的室温油分级等温淬火工艺获得低合金贝氏体球墨铸铁;研究了硼、铜、锰对贝氏体球墨铸铁组织和性能的影响,并讨论了球墨铸铁的性能滞后现象,即等温淬火后随时问延长硬度增加的现象。结果表明：硼和锰能提高硬度,降低韧性;铜提高韧性。合理加入合金元素有利于提高贝氏体球铁的性能。贝氏体球墨铸铁有性能滞后现象,其实质是溶质类拖曳作用。     

快速凝固Ti50Ni25Cu25块体合金的形状记忆性能研究

利用铜模喷铸法制备了具有形状记忆性能的高含Cu快速凝固Ti 50Ni 25Cu25合金棒材,并对其铸态和退火态组织进行了分析。详细研究了热处理温度对马氏体相变行为的影响,研究了Ti 50 Ni25Cu25合金棒材铸态和退火态的室温压缩力学行为,并测试了合金的形状记忆性能。各合金表现出良好的形状记忆性能和小的相变热滞。热处理提高了Ti 50 Ni 25Cu 25合金的相变温度和形状回复应变,550℃退火处理后预应变8%的Ti 50Ni 25Cu25合金棒材的形状回复应变约为2.2%。在500℃和550℃之间退火处理,有利于获得具有小相变热滞和优良形状记忆性能的合金棒材。     

氢化物对锆合金薄板焊缝断裂行为的影响

锆合金被广泛应用于反应堆的燃料管包壳材料,当服役过程中锆合金的力学性能改变时,对其力学性能完整性的评估至关重要。基于小尺寸三点弯曲试样,建立锆合金薄板焊缝的断裂韧度测试方法,完成腐蚀渗氢后锆合金焊缝在室温和360℃下准静态断裂韧度试验,分析氢腐蚀和温度对锆合金焊缝断裂性能的影响。研究结果表明,氢腐蚀和温度均能对锆合金焊缝断裂性能产生显著影响,由于高温条件下聚集在裂尖附近的氢化物溶解,使得360℃下锆合金渗氢焊缝断裂韧度较室温下的断裂韧度有显著提升。