65N6钢强韧化热处理工艺的研究

本文对６５Ｎ６钢应用于刀具方面的强韧化热处理工艺进行了系统研究,着重探讨了淬火温度和回火温度对６５Ｎ６钢的组织与性能的影响,提出了６５Ｎ６钢强韧化最佳配合的热处理工艺,为６５Ｎ６钢在刀具方面的应用提供了可靠的工艺依据。     

Al-Si系铸造铝合金强韧化技术及研究进展

本文从合金化、晶粒细化、变质处理、热处理工艺等方面详细综述了Al-Si系铸造铝合金强韧化技术手段及其研究进展,同时结合强韧化技术手段展望了未来Al-Si系铸造铝合金强韧化发展的重点及方向。     

含铌基体钢

这种钢具有良好的工艺性能,易于推广使用。热处理工艺温度范围宽,并可通过热处理工艺参数的选择来获得强韧性的不同配合。由于含铌基     

齿轮的强韧化处理

本文在新、旧工艺对比试验的基础上,提出了提高钢的强韧化方法。对低合金渗碳钢而言,采用低温短时间加热淬火工艺,可获得板条状马氏体组织,并能得到较高的强度和韧性。从马氏体形态学的观点出发,进一步发挥零件强韧潜力有着重要意义。     

37Si Mn Cr Ni Mo V钢微区成分、显微组织与断裂性能关系的研究

本文通过对37Si Mn Cr Ni Mo V钢强韧化研究,综合考察了现代主要强韧化工艺的强韧化水平,论述了热处理制度、微区成分、显微组织与断裂性能之间的关系。通过透射电镜观察,电子探针分析及其模拟计算,提出了试验用钢中孪晶马氏体的形成条件,分布状态以及对断裂韧性的影响。强调指出微区成分是热处理中最重要的结构参量。应用统计学方法建立了热处理制度与微区成分之间的关系。研究结果表明;微区成分越均匀,材料的断裂韧性就越高,这是因为微区成分决定了马氏体的亚结构。根据设计的各种热处理工艺所获得的微观组织及所具有的断裂性能,并结合对微区成分、原始组织的研究结果,提出了遗传热处理新工艺。与现行工艺相比,在保持材料等强度条件下,提高断裂韧性值25%,在等强、等断裂韧性的条件下,比超高温淬火工艺样品的冲击韧性值提高65%以上。达到了工艺、成分、组织的优良配合并使之材料的强韧性能得以充分发挥。     

20 CrMo双相钢力学性能与微观组织关系的研究

对20 CrMo钢在双相区淬火后回火得到的组织与常规性能的关系进行了研究。其目的是要找到使20 CrMo钢的各种性能配合最好的适当的淬火温度。试验结果表明:20 CrMo钢在820℃淬火后回火,强韧性匹配很好,认为20 CrMo钢临界淬火加热温度选为820℃为最佳。     

20CrMo双相钢力学性能与微观组织关系的研究

对20CrMo钢在双相区淬火后回火得到的组织与常规性能的关系进行了研究。其目的是要找到使20CrMo钢的各种性能配合最好的适当的淬火温度。试验结果表明：20CrMo钢在820℃淬火后回火,强韧性匹配很好,认为20CrMo钢临界淬火加热温度选为820℃为最佳。     

20CrMo双相钢力学性能与微观组织关系的研究

对20 CrMo钢在双相区淬火后回火得到的组织与常规性能的关系进行了研究.其目的是要找到使20CrMo钢的各种性能配合最好的适当的淬火温度.试验结果表明:20 CrMo钢在820℃淬火后回火,强韧性匹配很好,认为20 CrMo钢临界淬火加热温度选为820℃为最佳.     

提高无缝气瓶用34Mn2V钢强韧性的两种淬火工艺的研究

本文根据无缝气瓶用34Mn2V钢特点，对提高该钢强韧性的亚温淬火和低温淬火工艺进行试验研究，分析了工艺及组织变化对34Mn2V钢强韧性的影响，推荐了亚温淬火和低温淬火两种热处理工艺。     

自卸车用新型车斗底板钢的磨粒磨损特性研究

针对自卸车车斗上底板材料，开发了一种新型２８钢，研究了热处理工艺条件对其磨粒磨损性能的影响。结果表明，该钢奥氏体化后在空冷条件下即可得到下贝氏体和板条马氏体组织，并在８６０℃奥氏体化空冷条件下获得最佳强韧化效果，具有很好的耐磨粒磨损性能，是一种很好的车斗底板材料。     

预测钛合金超塑成形－扩散连接(SPF/DB)界面层的断裂韧度

提出根据超塑成形－扩散连接(SPF/DB)的工艺技术参数预测扩散连接界面层断裂韧度的计算方法,并对TC4/TA2连接件,开发了相应的界面层断裂韧度的分析和预测软件系统。该计算方法首先在理论分析和试验的基础上,建立扩散连接界面层成长模型,获得扩散连接件界面层厚度的计算公式,确定材料过渡参数m的计算方法;其次对已有的混合型外载的界面断裂准则进行修正,使其适用于扩散连接件界面层断裂时能量释放率曲线的函数模型。计算结果与试验结果吻合良好。分析结果表明：在允许工艺参数范围内,扩散连接件界面断裂韧度随成形温度、成形压力和保压时间的提高而提高。其中,成形压力影响最大,然后依次为保压时间和成形温度。为了提高扩散连接界面层的断裂韧度,必须通过界面层设计来提高其界面裂尖断裂混合度,而上述各工艺技术参数,正与其裂尖断裂混合度的大小密切相关。     

Mechanical behavior and numerical estimation of fracture resistance of a SCS6 fiber reinforced reaction bonded S13N4 continuous fiber ceramic composite

Continuous fiber ceramic composites (CFCCs) have advantages over monolithic ceramics: Silicon Nitride composites are not well used for application because of their low fracture toughness and fracture strength, but CFCCs exhibit increased toughness for damage tolerance, and relatively high stiffness in spite of low specific weight. Thus it is important to characterize the fracture resistance and properties of new CFCCs materials. Tensile and flexural tests were carried out for mechanical properties and the fracture resistance behavior of a SCS6 fiber reinforced Si₃N₄ matrix CFCC was evaluated. The results indicated that CFCC composite exhibit a rising R curve behavior in flexural test. The fracture toughness was about 4.8 MPa m^1/2 , which resulted in a higher value of the fracture toughness because of fiber bridging. Mechanical properties as like the elastic modulus, proportional limit and the ultimate strength in a flexural test are greater than those in a tensile test. Also a numerical modeling of failure process was accomplished for a flexural test. This numerical results provided a good simulation of the cumulative fracture process of the fiber and matrix in CFCCs.     

Interlaminar fracture toughness of CFRP laminates with silk fibers interleave

Interlaminar fracture toughness of CFRP laminates with silk fibers interleave was evaluated in this paper. Silk fibers were obtained from silkworm cocoon. Long silk fibers were wound around a bobbin and cut into specimen size. Resin films were bonded on both sides of a sheet of silk fibers. Silk fibers with resin films were put between [0₁₂] and [0₁₂] and cured by following the curing process. Evaluation of mode I and mode II interlaminar fracture toughness was accomplished by DCB and ENF test, respectively. Mode I interlaminar fracture toughness of CFRP laminates with silk fibers interleave was 59% higher than that of CFRP. Mode II interlaminar fracture toughness of CFRP laminates with silk fibers interleave was 44% higher than that of CFRP. It seems that CFRP laminates with silk fibers interleave will be useful to structures which need high interlaminar fracture toughness.     

Abrasion and edge fracture resistance estimation of hard materials by tribotesting method

The use of tools manufactured from hard materials is limited by their fracture toughness and there is a need for research aimed at increasing toughness without sacrificing good wear resistance. To aid in this objective, a simple and reliable integrated tribotesting method is needed in which a combined action involving both fracture and abrasion occurs. One such method currently developed is presented in this paper. The method is based on the concept of edge chipping during the initial transition stage of abrasion wear, which is controlled by a brittle fracture process. The empirical relationship between mass loss as a result of edge chipping during the initial transitional stage of abrasive wear and fracture toughness is presented in the form of formulae. Copyright © 2007 John Wiley & Sons, Ltd.     

高强度高韧性云母微晶玻璃的热压制备和力学性能

采用热压形变工艺,成功地制备出了具有择优取向的高强度高韧性云母微晶玻璃。用三点弯曲法和单边切口梁（SENB）法在不同工艺条件下对微晶玻璃的抗弯强度和断裂韧度进行了测定。结果表明：在热压形变过程中,玻璃相发生粘性流动,云母晶体随之转动并产生择优取向,增强了对平行于热压方向的裂纹的偏转和分叉作用,材料的力学性能得到显著提高。基础玻璃在950℃晶化3h并经1000℃热压形变处理后,所得的云母微晶玻璃在热压方向上的抗弯强度和断裂韧度分别可达390Mpa和2.92MPa·m{sup}(1/2),比热压前提高了2倍多。     

最弱链模型估算局部脆性区尺寸对焊接热影响区断裂韧度的影响

从最弱链模型的物理本质出发，探讨了影响焊接热影响区脆性断裂的主要因素。在一定的断裂韧度前提下，随着局部脆性尺寸的增加，焊接热影响区的脆断概率增加。当断裂概率一定时，局部脆性区尺寸增加，焊接热影响区断裂韧度下降。文中讨论了最弱链模型中各参数对断裂概率密度及断裂韧度值分布的影响。．     

Edge failure as a means of concurrently estimating the abrasion and edge fracture resistance of hard-metals

Fracture toughness is often the major limiting parameter governing the use of tools manufactured from hard materials and there is a need for research aimed at increasing toughness without sacrificing good wear resistance. To aid in this objective, a simple and reliable integrated testing method is needed in which a combined action involving both fracture and abrasion occurs. One such method currently developed is presented in this paper. The method is based on the concept of edge chipping during the initial transition stage of abrasion wear, which is controlled by a brittle fracture process. The limitation of the method for tougher materials, such as tool steel, as well as for very brittle materials such as ceramics is also indicated. The empirical relationship between mass loss as a result of edge chipping during the initial transitional stage of abrasive wear and fracture toughness is presented in the form of formulae.     

Dynamic fracture characteristics of highly brittle materials by using Instrumented Charpy Impact Test

In This study we investigate the dynamic fracture characteristics of a tungsten carbide cobalt (WC-6wt%Co) composite material. The dynamic fracture initiation toughness and some of the dynamic fracturing characteristics are evaluated by using the Instrumented Charpy Impact Testing (ICIT) procedure. The dependence of measured time-to-fracture on the tup impact velocity and the dynamic fracture toughness for the WC-6wt%Co composite material are obtained by using ICIT. The effect of the loading rate on fracture initiation toughness is found to be negligible when the time-to-fracture is on the order of 50μsec. At significantly higher rates of loading it is impossible to determine the apparent dynamic fracture initiation toughness because of the influence of the inertia force on fracture loading. It is found that the impact velocities affect the time-to-fracture significantly at lower impact velocities for various engineering materials. It is shown that with the decrease of tup impact velocities the time-to-fracture is increased and the dynamic fracture initiation toughness converges to static fracture toughness.     

力学不均匀性对焊接接头动态J积分影响的实验研究

用真空电子束焊的方法建立焊接接头的“软夹硬”非均匀体模型。用示波冲击的试验方法测出试件的动态断裂韧性,用该模型研究了焊接接头的力学不均匀性对其动态J积分的影响。结果表明,裂纹位于硬区材料,断裂韧性值理接近硬区材料,与软区材料的断裂韧性值差别较大;随夹层宽度增加,断裂韧性值减小,夹层宽度到某一值时,断裂韧性值趋于稳定。     

不同类型接管安全端焊接接头常温断裂韧性对比研究

对带镍基合金隔离层和无隔离层两种不同类型接管安全端焊接接头的常温断裂韧性进行对比研究,研究结果表明:接头焊缝区的J-R阻力曲线和断裂韧性高于SA508区域,低于316L区域。界面裂纹的J-R阻力曲线和断裂韧性最低,界面区域的延性裂纹起裂和扩展阻力最小。带隔离层接头中熔合区、热影响区和焊缝中心区的J-R阻力曲线和断裂韧性J 1c略高于无隔离层接头的对应区域。无隔离层接管安全端接头的J-R阻力曲线和断裂韧性可以达到带隔离层接头的水平。