表面渗碳对17GrNiMo6矿用圆环链的显微组织及其力学性能的影响

针对17GrNiMo6矿用圆环链表面易损坏的问题，采用渗碳+高温回火+淬火+低温回火工艺对其进行热处理，研究了热处理工艺对渗碳层的显微组织、显微硬度、渗碳层深度、硬化层深度以及圆环链的拉伸性能和破断性能的影响。结果表明：采用热处理方法可以提高渗碳层表层的显微硬度，最高可达631.3 HV。其表层组织为针状马氏体，碳化物主要分布在晶界处，次表层组织为针状和少量板条马氏体，芯部组织主要为板条马氏体和微量贝氏体，显微硬度约为440.3 HV。试样渗碳层深度达3.8 mm，硬化层深度达2.3 mm。随着碳原子的渗入，试样抗拉强度和屈服强度相比于未热处理时均有所提高，但其伸长率和收缩率则均下降，破断负载在渗碳处理后增加并超过链条原件负载的14.58%，采用表面渗碳处理方法试样的破断负载和伸长率均达到国标对C级别圆环链的要求。     

低温设备和管道用304不锈钢热诱发马氏体相变特征研究

借助于X-射线衍射技术,研究了304亚稳奥氏体不锈钢热诱发马氏体相变倾向.研究结果表明:C、Mn、Cr和Ni接近下限,钢的稳定性严重下降,固溶态即形成少量α'马氏体,液氮内冷却后α'马氏体急剧增加,并伴随有ε马氏体形成,室温发生应变诱发ε和α'马氏体相变,而且室温预应变进一步增大低温热诱发马氏体相变倾向.ε马氏体的变化与α'马氏体的累积量有关,α'马氏体较小时,ε马氏体量增加,α'马氏体累积到一定程度后ε马氏体下降,直至消失.     

低温应变片测定ZTC材料的马氏体相变温度

本文用电阻应变片测定了ＺＴＣ陶瓷材料的马氏体相变温度。所需试样不需特殊加工，是一种极为方便的测试方法。     

SLM制备TC4合金微观结构研究

采用SLM技术制备TC4钛合金试样,对TC4的组织特点进行研究,并观察退火处理对TC4成形件显微组织的影响。通过SLM技术制备的TC4合金试样组织主要为α相和针状马氏体,且式样中未发现β相的存在,并存在大量位错塞积。经退火处理后高密度位错消失,针状马氏体分解,组织细化,强度有所下降但塑性提高。     

注射成型纤维增强试样的机械性能模拟

采用Moldflow软件对注射成型纤维增强热塑性塑料的拉伸试样进行模拟研究.详细分析了注塑成型拉伸试样的纤维取向结构及由此引起的机械性能变化.分析表明:试样标距位置的纤维平均取向较好、皮芯结构不明显,标距外的两端部及两过渡位置的纤维平均取向不佳、皮芯结构较为明显;试样的物理性能参数受到取向影响而呈现各向异性.结合纤维取向分析、拉伸模量分析及泊松比分析,对注射法成型拉伸试样的方法进行初步探讨.     

Mg—PSZ陶瓷热处理与四方析体马氏体相变温度关系的研究

采用带有液氮负温裝置的LK-02型高速淬火膨胀仪对已获得工业应用的、含10mol％MgO的Mg-PSZ陶瓷的热处理条件与其中t-ZrO_2的马氏体相变温度(M_4、M_6)及可相变t-ZrO_7析体量的关系进行了研究,认为:t-ZrO_2析体的粒径及其热处理过程中的应力应变状态是决定或影响马氏体相变温度高低和在应力诱导下可相变t-ZrO_2量的两个基本因素;采取1420℃和1100℃的综合热处理,与在1420℃或1100℃进行单一温度热处理相比,易于控制M、和M_4值,且能保证较高的可相变t-ZrO_7析体量,是优化Mg-PSZ结构和性能的一种值得进一步进行研究的热处理工艺。经1100℃、4b热处理的Mg-PSZ试样的“Δl-T”曲线的低温端未观察到明显的表征马氏体相变的膨胀效应。     

五价钽、锂掺杂对Y-TZP微观结构和性能的影响

在前人工作的基础上,本文作者进一步深入细致地分析了总结了Ｎｂ２Ｏ５和Ｔａ２Ｏ５对Ｙ－ＴＺＰ微观结构和宏观性能的影响并提出了自己的见解,研究发现Ｎｂ２Ｏ５和Ｔａ２Ｏ５的添加使得Ｙ－ＴＺＰ轴比及热膨胀各向异性增大,马氏体相变起努温度升高,可相变,ｔ－ＺｒＯ２含量上升有利于材料机械性能的提高。     

金属马氏体相变研究及其向无机非金属材料增韧的过渡

本文概述了金属中马氏体的相变特征和类型,影响马氏体相变的因素(如降低温度、提高冷却速度、减小原始相晶粒度、应力),以及马氏体在加热时的转变形式,以期对无机非金属材料的相变增韧做借鉴。     

填充方式对熔融沉积成型试件力学性能的影响

在将聚乳酸(PLA)作为原料的熔融沉积成型(FDM)实验中,分别研究了10%、20%、30%、40%、50%、60%、70%、80%、90%、100%10种填充率,与直线型、斜线型、蜂窝型、三角型和波浪型5种填充路径对试样拉伸强度和断裂伸长率的影响。研究结果表明,随着试样填充率的增加,拉伸强度逐渐增大。当填充率 60%时,拉伸强度的提升效果更显著。随着填充率的提高,试样的断裂伸长率呈先增加,后降低,再增加的趋势。当试样采用斜线型填充路径时,试样的拉伸强度的提升效果最佳。此外,可以通过材料力学构建的理论模型计算得到试件的拉伸强度。     

热处理对60CrMnMo轧辊钢微观组织与硬度的影响

研究了一次正火、二次正火和油淬三种热处理工艺对60Cr Mn Mo轧辊钢组织与性能的影响,并对一次正火、二次正火和油淬后的试样进行560℃、580℃和600℃回火处理。运用金相显微镜、硬度测试机等手段对不同工艺处理后的试样进行组织和性能检验分析。结果表明:不论是否进行回火,油淬后的60Cr Mn Mo轧辊钢试样硬度高于正火态试样。对于560℃、580℃和600℃回火处理,一次正火和油淬后的试样硬度值呈现下降趋势,而二次正火后的试样是呈现先上升后下降变化趋势。热处理后的60Cr Mn Mo轧辊钢金相组织各不相同,一次正火后的组织为贝氏体,二次正火后的组织为珠光体和铁素体,油淬后的组织为马氏体和碳化物。     

碳纤维复合材料压力容器的透声性能研究

以环氧树脂为基体材料,分别以S2高强玻璃纤维和T700碳纤维为增强材料,采用缠绕成型工艺,制备了玻璃纤维复合材料（GFRP）透声试件和碳纤维复合材料（CFRP）透声试件;测试了试件的透声性能,为成功研制碳纤维复合材料透声压力容器提供依据。结果表明：CFRP的透声性能和力学性能远远优于GFRP;内衬层对容器的透声性能影响不大;研制的碳纤维透声压力容器达到了满意的透声效果。     

Glare 层板试样制备对其性能的影响研究

介绍了Glare层板的试样制备对其性能的影响。Glare层板试样制备主要包括试样设计与加工、加强片粘接以及裂纹预制等工艺,不合理的试样设计、加强片粘接缺陷以及测试工作区的加工误差都会对测试产生重要影响。     

聚合反应釜壳体结构优化设计

以聚合反应釜的优化设计为案例,对整体夹套容器设计提出优化方案并应用于实践。通过设计计算可知在设计参数确定的情况下,只有设置加强圈才能得到更为合理的壳体厚度。分析确定了加强圈的设置位置及间距,设计了满足要求的外压加强圈。为满足安装要求,对耳式支座的设置进行了分析计算。     

奥氏体不锈钢应变强化容器技术进展

应变强化技术的应用可以实现奥氏体不锈钢压力容器的轻型化设计,这对于节约能源、降低成本具有十分重要的意义。本文主要介绍了奥氏体不锈钢室温应变强化技术基本原理和相关要点。分析了国外应变强化不锈钢压力容器标准的结构设计、不锈钢材料许用应力值的选取等。     

奥氏体不锈钢压力容器应变强化设计技术探讨

应变强化技术能够有效的提高奥氏体不锈钢的屈服强度,从而减小奥氏体不锈钢压力容器的设计壁厚,减轻容器的重量,降低重容比,减少容器制造与运输过程中的能耗,实现压力容器的轻型化。本文介绍了奥氏体不锈钢压力容器应变强化的基本原理和基本设计思路,并从强度、蠕变、疲劳、均匀腐蚀、应力腐蚀开裂(SCC)等方面综述了奥氏体不锈钢应变强化后的性能变化,并提出进一步研究的方向,以实现奥氏体不锈钢压力容器轻型化设计。     

Numerical study on notched steel plate with center hole strengthened by CFRP

Steel members could be damaged and fail to fulfill the requirements of safety after long-term service. Carbon fiber reinforced polymer (CFRP) strengthening turns out to be an excellent method for prolonging its service life. The strengthening technique has been extensively studied in recent decades, however, few researchers concerned about the simulation of steel plates with center hole strengthened by CFRP. Therefore, its mechanical performance was investigated numerically in this study. The numerical results were compared with the experimental results and an acceptable agreement was reached, which verified the validity of the numerical model. A parametric study was conducted, in which the interfacial stress distribution change with CFRP elastic modulus, thickness and strengthening form was analyzed. For fully covered CFRP strengthening, increasing of elastic modulus and thickness of CFRP plates can enhance the stiffness of steel plates, however, it has insignificant effect on debonding load and obvious decrease on ultimate load. While the partially covered CFRP bonding strengthening can also upgrade the stiffness with CFRP elastic modulus and thickness, the effect to both of debonding load and ultimate load is minimal.     

Analysis of the specimen shape and aging protocols in the adhesive strength between dentin and resin composite

The objective of this study was to evaluate the aging protocols and the specimen shape (sticks and dumbells) in the adhesive strength between dentin and resin composite during micro-tensile stress. The specimens were submitted to no aging protocol, mechanical cycling (using macro and micro-rotation methods), thermal cycling and micro-tensile test. The stress distribution for the two specimen shapes was performed by finite elements analysis. Data were submitted to 3-way ANOVA and Tukey Test (α = 0.05). There is no statistical difference considering the interactions among the factors: specimen shape, thermal cycling, and mechanical cycling. Also, the mechanical cycling, for both methods, micro or macro-rotation, and the thermal cycling did not affect the adhesive strength of the samples. However, the specimen with the dumbbell shape showed higher adhesive strength (16 ± 3 MPa) than the stick shape specimen (11 ± 2 MPa). The stress distribution in dumbbell shape was more homogeneous than in the sticks. It can be concluded that the aging protocols tested were not enough to degrade the adhesive interface and the dumbbell shape specimen is better to predict the real adhesive strength developed in the interface.     

奥氏体不锈钢压力容器的应变强化技术

介绍了应变强化基本原理,并分析奥氏体不锈钢压力容器应变强化两种模式——常温应变强化Avesta模式和低温应变强化Ardeform模式。同时,分析比较几种压力容器标准关于奥氏体不锈钢材料的许用应力选取,其中欧盟EN13445压力容器标准奥氏体不锈钢屈服强度按σ1.0选取,材料安全系数取值较低,非常实用。     

稀土氧化物对钛酸铝陶瓷显微结构和力学性能的影响

研究了添加稀土氧化物Y2O3和Y2O3+Nd2O3对钛酸铝陶瓷的烧结温度、力学性能和显微结构的影响.结果表明,添加1%的稀土氧化物可以降低钛酸铝陶瓷的烧结温度,改善其显微结构,提高其力学性能,尤其是添加1%的复合稀土氧化物(Y2O3+Nd2O3)后,钛酸铝陶瓷的抗折强度和断裂韧性是未添加的试样的1.96倍和1.82倍.其性能提高的主要原因是由于稀土元素的细晶强化、净化界面、固溶强化、自增韧补强等作用.     

Shear properties of isotropic conductive adhesive joints under different loading rates

Epoxy-based conductive adhesives have been widely used in the electronic field given the lead-free development of electronic packaging. The conductive adhesive joints must be subjected to shear loads during the service of electronic products considering the mismatch in mechanical properties between packaged chip and substrate. In this study, INSTRON 5544 universal material testing machine was used for tensile–shear tests of isotropic conductive adhesive joint specimens, which were prepared using pure copper plate adherend in the form of single-lap joints. Four loading rates, that is, 0.05, 0.5, 5, and 10 mm/min, were adopted. The relationship between shear load and displacement of two overlapping copper plates is deduced from a mechanical perspective. A mechanical model of the conductive adhesive shear specimen was developed by introducing dimensionless parameters, which are obtained from interfacial fracture energy and shear strength, to interpret the effect of loading rate on the shear properties of the conductive adhesive specimen considering the loading rate. Results show that this model can effectively reflect the relationship between shear load and displacement in the range of 0.05–10 mm/min.