EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Li ALLOY WITH Ca ADDITION

Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The billets can be rolled to thin sheets at room temperature, from which it is obvious that the addition of Ca improves alloys ormalin. while it decreases with the excess addition of Ca. The results also show that the ultimate tensile strength （UTS） and yield strength （YS） of the alloy with lwt% Ca may rise by 28% and 25%, respectively, however, the elongation decreases. It is clarified that the adsorption of proper Ca on the grain boundaries refines α-Mg and improves the tensile properties, but the presence of excess Ca and stable Ca2Mg6Zn3phase worsens the elongation.     

A STUDY OF RATE-DEPENDENCE AT ELEVATED TEMPERATURE FOR AN Al-Cu-Mg ALLOY

The hot deformation of an Al-Cu-Mg alloy was studied in the two temperature ranges (room temperature-300℃ and 400℃-480℃). The rate-independent flow curves are typical of elasto-plastic response with significant work hardening followed by strain softening below 300℃. Similar dislocation structures with high density tangled into grain interiors were observed by TEM, which suggests that the process of obstacles arresting mobile dislocations results in this macroscopically rate-independence. At 400-480℃, all rate dependent flow behaviors characterized by a continuous softening after an initial work hardening at a small plastic strain show large tensile elongations. Long dislocation segments around the second phases infer their good mobility to climb across obstacles. Grain boundary morphology observed by TEM suggests that the capacity of the grain boundaries to absorb the dislocations sensitively accounts for the rate-dependent mechanical properties.     

德国的焊接生产(2)

4　人才培养德国社会教育的普及程度已达到世界先进水平。在她的 343所国家大学里 ,有超过 180万的大学生在学习。德国实行不间断的普通职业教育方法 ,包括人员的培训及考核。在很多部门中 ,德国的专家培训和考核大纲标准被当作欧洲和国际相应项目标准的研究基础。从 2 0 0 0年开始 ,德国在教育上投资的年增长额为 10 0万马克。这完全符合世界上向高科技人才培训增加投资的趋势。在德国 ,有将近 4 6万人在科技及为科技服务的领域里工作。德国政府拨出 2 .2 7%的ＢＢП(国民经济总产值 )来发展国家的科学技术 ,在这方面 ,她在日本 (2 .98% )…     

Ti9Al合金的氢塑性效应

采用真空自耗电弧炉熔炼制备Ti9Al合金，通过渗氢处理显著提高氢含量，在凸轮塑性试验机ЧПИ-2上以10mm／min的速度进行热模拟试验。研究发现：氢可以降低Ti9Al合金的相变温度，扩大α β区的温度范围；氢作为卢稳定剂会妨碍或完全抑制以Ti3Al为基的α2相的析出；钛合金的氢合金化可促使卢相在更低温度下稳定化，明显地提高了Ti9Al合金塑性。     

钛的工业应用

钛材的工业应用已经扩大到许多领域,钛材具有吸引力的地方在于它们具有优良的耐蚀性和高的比强度,这在航空应用中已得到了充分肯定。工作纯钛最普通的用途是用于热交换器。为了提高冷凝器的可靠性,核电站和火力发电站的全钛冷凝器不仅使用了焊接钛管而     

未来十年的粉末冶金技术

这是美国粉末冶金学会金属粉末工业联盟执行主席罗尔在八○年国际粉末冶金会议上的开幕词,他从十个方面论述了80年代的粉末冶金技术。有丰富的究末:在美国,目前还没有任何一种金属粉末是短缺的,特别是铁粉,生产能力已达到一个新的水平,到1981年年产几乎可达33万吨,稍加扩充,到1985年为止年产可达45.7万吨。而目前所消耗的铁粉即使     

Ti-15-3:一种新的可冷成形的板材钛合金

Ti—15V—3Cr—3Al—3Sn(简称Ti—15—3)是一种新的亚稳定β板材合金,用于要求冷成形和高强度的地方。Ti—15—3当初是由美国空军研制的,现已成为某些航空构件的标准材料,同时,在其它部门亦是强有力的选材对象。原始的想法是发展一种经济的、能够冷加工成形的板材钛合金,以便降低加工制造成本,减轻现场维修工作量。这种想法实现了。与必须在手控轧机上热轧的现行α-β合金相比,Ti—15—3合金因可以加工成带材而显示出成本上的优点。如果说α-β合金在大多数情况下还需要热成形的话,Ti—15—3却能冷成形到相当复杂的形状。此外,该合金是可焊接的,可以时效处理到高强度,对盐水等环境比较不敏感。最后,Ti—15—3呈现出较低的方向性,其退火态性能对工艺参数不甚敏感。     

还原方法对粉末冶金钼性能的影响

钼粉的形态取决于是由升华的三氧化物MoO_3还是由二钼酸铵(NH_4)_2Mo_2O_7制得的金属,还取决于还原过程使用的还原剂。由于粉末形态不同,使烧结产品的密度不同,同时影响再结晶溫度、强度和延性。     

THE PREPARATION AND CHARACTERISTICS STUDY OF TiNxOy SPECTRAL SELECTIVE ABSORBING FILM BY MAGNETRON SPUTTERING

Spectral selective absorbent film is a crucial factor for the solar heating device. There are many kinds of spectral selective absorbing film made by different ways. TiNxOy thin film with excellent spectral selecting absobent property were successfully prepared by DC magnetron sputtering with Ar as working gas, N2 and O2 as reactive gas, 99.9% titanium as the target and is copper slice as the substrate. In this article, the optical characteristics and microstructure of TiNxOy thin film were studied. Inputing O2 can decrease the reflection of the visible lights, and double layer film can get good absorption for solar energy.