固溶处理对铍材力学性能的影响

利用稳定低氧的气流冲击研磨铍粉，研究了固溶处理对冷、热等静压铍材和真空热压铍材力学性能的影响。结果表明，无论是热压铍材还是等静压铍材，其固溶态力学性能均比压制态低；固溶时析出的Be2SiO4导致BeO的聚集，同时，由于原料中铁含量较低，不能形成有效的固溶强化，是固溶态势压铍材力学性能降低的主要原因。     

5083合金镁含量对其性能的影响

通过对5083合金镁含量的调整，研究镁对热轧板材最终力学性能的影响。试验用5种不同Mg含量的热轧板材对金相和力学性能进行测试，结果表明随着Mg含量的提高，5083合金板材的力学性能呈增大趋势，并且在Mg含量和Mn含量都较高时，获得较好的综合力学性能。     

化学成分及退火工艺对H62黄铜组织与性能的影响

对锌含量不同的H62黄铜冷轧带材进行了退火处理，然后对其进行力学性能测定和金相分析。结果表明，锌含量及退火工艺对材料的组织和性能有明显影响。     

关于非调质钢力学性能检验试验条件的探讨

本文分析了目前国内非调质钢力学性能检验试验条件存在的问题。研究了加热温度,自然放置时间和低温加热处理对非调质钢YF45MnV热轧材力学性能的影响。提出了锻造用和直接切削加工用非调质钢力学性能检验合理可行的试验条件。     

退火处理对钼铼合金箔材性能的影响

钼铼合金具有优良的室温塑性,作为重要元器件应用于电子、半导体等行业。钼铼合金通过粉末冶金工艺方法制备,并经过热轧和冷轧变形,得到需要厚度尺寸的钼铼合金箔材。钼铼箔材还需要进行弯曲、冲压等加工工序制作成零部件应用,对箔材的力学性能有很高的要求。轧制后的退火处理不仅可以消除应力,还有助于改善材料的性能,因此退火处理对于钼铼箔材非常重要。本文通过对0. 05 mm钼铼合金[Mo-35%(质量分数) Re]箔材进行去应力退火、部分再结晶退火和完全再结晶退火等不同退火制度的研究,分析了显微组织的变化,比较了力学性能和杯突性能。试验结果发现,钼铼箔材经过部分再结晶退火处理后,材料具有最优的塑性和杯突值,这对箔材的后续机加工产生有利的影响。     

冷却方式对Q195线材力学的性能影响的研究

冷却方式对Q195线材的力学性能有很大影响,冷速过快和过慢都会对Q195线材组织和力学性能产生不良影响,本文在实验基础上对Q195线材轧制过程中的冷却工艺进行了调整,改善了Q195线材组织和力学性能。     

大规格6082T6铝合金棒材力学性能控制

通过试验研究，分析了6082T6大规格棒材力学性能的主要影响因素，并指出热处理工艺是影响6082T6大规格捧材力学性能的关键因素，棒材力学性能偏低的主要原冈是生产中加热保温时间不足够长所致。     

电致塑性拉拔及电致塑性处理技术的应用

电塑性拉拔技术是近年来快速发展的一种新型的金属丝材加工技术.该技术是利用高密度脉冲电流在金属丝材塑性变形过程中产生的电塑性效应来促进丝材的变形、降低拔制力、提高丝材的成型极限、改善丝材的显微组织结构和其综合力学性能.系统地介绍了电塑性效应、电塑性拉拔工艺装置和电塑性处理技术在不锈钢丝以及高碳钢丝中的应用.     

7050铝合金薄壁管挤压工艺

介绍了7050铝合金薄壁管材的规格和质量要求、工艺路线以及主要生产设备。在大量工艺试验基础上，研究探讨了7050铝合金薄壁管材的挤压工艺、热处理工艺及矫直方法。尺寸测量和力学性能结果表明，所加工7050铝合金薄壁管材完全满足用户要求。     

2024/7075异质铝合金电弧增材成形界面的组织性能

采用电弧增材制造技术在7075铝合金基材上成形2024铝合金试样，研究了不同工艺参数下异质铝合金界面的成形工艺性，以及热处理前后2024/7075异质铝合金电弧增材成形界面的显微组织和力学性能。结果表明，电弧增材成形过程的热输入增加，则2024/7075异质铝合金之间的铺展效果更好；2024/7075异质铝合金电弧增材界面区域内Mg、Zn、Cu元素含量较高，沉积态界面组织第二相沿结合界面连续分布，热处理态界面组织第二相粒子呈现点状、棒状、块状弥散分布；热处理后2024/7075异质铝合金界面的抗拉强度为388MPa，与沉积态相比力学性能显著提高。     

Differences between Tensile Properties of WAAM SS304 Components in Different Directions

Wire arc additive manufacturing (WAAM) is particularly suitable for manufacturing large metal structure components. However, the anisotropy of mechanical properties of WAAM components cannot be avoided, which makes the mechanical properties of WAAM components unstable and seriously limits its engineering application. Herein, the tensile samples for 304 stainless-steel thin-walled structures along three directions (longitudinal, diagonal, and transverse) of the deposition layer are intercepted. The mechanical properties of the components are 9.3–54.6% higher than the standard values. The samples have obvious anisotropy characteristics. Samples with diagonal direction show the best mechanical properties, which are not affected by process parameters. The better the forming quality, the higher the mechanical properties of the samples. By correlating the mechanical properties results of the samples with the microstructures, it is found that very fine dendrites grow along the deposition direction in the samples, and this unique microstructure leads to the anisotropy of the mechanical properties. Under the action of uniaxial tensile load, the growth direction of precise dendrite in the sample with diagonal direction is almost the same as the slip direction of the maximum dislocation plane, which is the reason for the excellent mechanical properties of the sample with diagonal direction.     

烧结温度及Y2O3对9Cr-RAFM钢性能的影响

采用粉末冶金技术,以球磨-模压-真空烧结工艺制备2种9Cr-RAFM钢:以0.3%Y2O3(质量分数)为弥散相的ODS 9Cr铁基高温合金和不添加Y2O3的Non-ODS 9Cr铁基高温合金。研究烧结温度及Y2O3对RAFM钢的力学性能和微观组织的影响。研究结果表明:采用球磨-模压-真空烧结工艺制备的ODS合金的综合力学性能高于Non-ODS合金,并且在1 390℃烧结,保温2 h条件下制备的ODS合金具有最佳的综合力学性能(抗拉强度600 MPa,伸长率23.1%)。并对不同球磨时间的合金粉末进行XRD物相分析,用SEM及能谱分析技术研究Y2O3影响RAFM钢的微观组织成分和力学性能的机理。     

Biomechanical properties of human os calcanei: relationships with bone density and fractal evaluation of bone microarchitecture

The relationship between bone strength and bone mass is well established. The link between trabecular microarchitecture and biomechanical properties has been less extensively explored. To address this question, we have tested the mechanical behaviour of calcaneus bone samples and investigated the correlations between mechanical properties on the one hand, bone density and fractal analysis of microarchitecture on the other hand. Mechanical properties of 43 human os calcanei were determined by uniaxial compression testing of samples from tuber calcanei. Ash density, bulk density and dual energy X-ray absorptiometry of the samples were measured. Fractal analysis of the trabecular bone on calcaneus radiographs was performed by two estimators derived from the fractional Brownian motion model. The mechanical properties of human os calcis were found to correlate with age and density measurements. Fractal parameters derived from the bone texture analysis showed weaker but significant correlations with bone strength. Fractal analysis of texture could account in part for the variations of bone strength, but in this study cannot explain better than density the mechanical properties of trabecular bone. Nevertheless, it provides a non-invasive means of assessing molecular bone microarchitecture.     

Mechanical Properties of Reconstituted Australian Black Coal

Coal is usually highly heterogeneous. Great variation in properties can exist among samples obtained even at close proximity within the same seam or within the same core sample. This makes it difficult to establish a correlation between uniaxial compressive strength (UCS) and point load index for coal. To overcome this problem, a method for making reconstituted samples for laboratory tests was developed. Samples were made by compacting particles of crushed coal mixed with cement and water. These samples were allowed to cure for four days. UCS and point load tests were performed to measure the geomechanical properties of the reconstituted coal. After four days curing, the average UCS was found to be approximately 4?MPa. This technical note outlines some experimental results and correlations that were developed to predict the mechanical properties of the reconstituted black coal samples. By reconstituting the samples from crushed coal, it is hoped that the samples will retain the important mechanical and physicochemical properties of coal, including the swelling, fluid transport, and gas sorption properties of coal. The aim is to be able to produce samples that are homogeneous with properties that are highly reproducible, and the reconstituted coal samples can be used for a number of research areas related to coal, including the long-term safe storage of CO2 in coal seams.     

On the Relationship between Mechanical Properties and Mechanisms of Plastic Deformation in Metastable Austenitic Steels

The requirements of the automotive industry for materials exhibiting increased structural performances are continuously increasing. These materials must remain ductile during the forming operations while also exhibiting improved strength and energy absorption capacities. New highly alloyed steel grades have been studied for a few years now, due to their exceptional mechanical properties resulting from interactions between dislocation plasticity, transformation plasticity and mechanical twinning. This study deals with the mechanical properties of steel grades presenting high manganese compositions. At room temperature, several phase transformations (γ→α', γ→? and ?→α′) were found to occur when the samples are deformed. The effect of different annealing conditions on the mechanical properties and the transformation sequence is analysed. The evolution of the work‐hardening of the samples is interpreted in connection with the kinetics of the phase transformations.     

Effects of Nanometer Carbon Black on Performance of Low-Carbon MgO-C Composites

The low-carbon magnesia-carbon(MgO-C)composites containing 3%(mass fraction,the same below)carbon were prepared by adding various types of carbon black(CB).The mechanical properties,oxidation resistance at 1100 ℃ in oxidizing atmosphere,and thermal shock resistance after 5 times dipping in 1600 ℃ molten steel of the low-carbon composite samples were investigated,compared with a commercial high-carbon MgO-C composite containing carbon of 16%.The results show that the mechanical properties,oxidation resistance and thermal shock resistance of the low-carbon samples are improved with the decrease of CB particle size.Thermal shock resistance of the low-carbon sample containing nanometer CB N220 is obviously better than that of other low-carbon samples,and reaches the level of the high-carbon samples.     

矩形截面拉伸试样尺寸对钢板力学性能测试结果的影响

通过板材减薄试样和全截面试样拉伸实验力学性能的对比统计分析,探讨了两种试样对力学性能的影响,结果表明：采用坯材厚度不变的全截面试样的拉伸实验结果与减薄试样相比,屈服强度、抗拉强度无明显变化,断后伸长率提高。     

Effect of antimony on the creep fracture of stainless steel

Stainless steel samples doped with various contents of Sb were crept under the same conditions. With respect to the base material, a low content of Sb (0.1 wt pct or 0.2 wt pct) is found to improve creep strength and creep ductility of the alloys whereas the addition of 1 wt pct Sb decreases the mechanical properties. The microstructure of the samples was examined quantitatively by scanning electron microscopy. The improvement of mechanical properties is attributed to a reduction of the nucleation rate and of the growth rate of cavities. In order to predict the strain to fracture, a criterion on the fraction of grain boundary area cavitated is proposed.     

Starch consolidation of M3/2 high speed steel powder – influence of microstructure on mechanical properties

Abstract

The influence of microstructure on the mechanical properties of starch consolidated super solidus liquid phase sintered AISI type M3/2 high speed steel powder has been evaluated. Hardness measurements, Rockwell C indentation and scratch testing were used to evaluate the mechanical properties and light optical microscopy and scanning electron microscopy were used for post-test characterisation. The results show that it is possible to starch consolidate and sinter large particle size high speed steel powder to obtain microstructures with high mechanical strength. However, the results show a strong correlation between the as sintered microstructure and the resulting mechanical properties and illuminate the importance of having a dense and isotropic microstructure in order to meet engineering requirements in demanding applications. Consequently, the failure mechanisms observed during indentation and scratch testing can be related to residual pores, present in the low temperature sintered samples, and a coarse microstructure with eutectic carbides, present in the high temperature sintered samples.