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关键词： 冲压模具材料   冲压工艺   强化处理技术   碳素工具钢   低合金工具钢   高速钢  

摘要： 冲压工艺是我国工业生产中最常用的一种金属加工方法,冲压模具是其使用媒介。冲压模具可以有效提高产品的生产效率,因而被广泛运用于各个制造行业之中,发展迅猛,但随着制造业需求的不断增加,冲压模具发展面临着挑战。基于此,文章先对冲压模具材料进行分类,再对冲压模具材料的适用机理进行研究,提出了模具材料的选用方法,并归纳分析出模具材料的强化处理技术,以不断提高冲压模具的性能和整体质量。

关键词： 第一学段   特点体认   分类整理   独立识字  

摘要： 义务教育阶段的语文课程内容整合程度不断提升,分三个层面设置学习任务群,其中第一层为基础型学习任务群“语言文字积累与梳理”。本文在实践的基础上,认为本任务群在第一学段的实施须围绕“特点体认”与“分类整理”展开。因此,第一学段的教学须把握三个要点:在高度整合的学习内容中,体认常用汉字特点,培养自主积累的习惯;以丰富多彩的学习情境为兴趣支点,驱动学生在体认特点和分类整理中发展独立识字能力;根据学段特点,设计具有逻辑关联的实践活动,帮助学生逐步形成分类整理意识。

关键词： Mg-Ga alloys   solid solution strengthening   damping capacity   Granato-Lücke model  

摘要： The mechanical behaviors and damping capacities of the binary Mg−Ga alloys with the Ga content ranging from 1 to 5 wt.%were investigated by means of optical microscope(OM),scanning electron microscope(SEM),X-ray diffraction(XRD),hardness test,tensile test and dynamic mechanical analyzer(DMA).The hardness(HV_(0.5))increases with the increase of Ga content,which can be described as HV_(0.5)=41.61+10.35c,and the solid solution strengthening effect∆σ_(s)of the alloy has a linear relationship with c^(n),where c is the molar fraction of solute atoms and n=1/2 or 2/*** exhibits a stronger solid solution strengthening effect than Al,Zn or Sn due to the large atomic radius difference and the modulus mismatch between Ga and Mg *** addition of Ga makes the Mg−Ga alloys have better damping capacity,and this phenomenon can be explained by the Granato−Lücke dislocation *** lattice distortion and the modulus mismatch generated because of the addition of Ga increase the resistance to motion of the dislocation in the process of swinging or moving,and thus the better damping capacity is acquired.

关键词： 铜阳极泥   稀散元素   真空挥发   气液相平衡   二元合金   成果简介   预处理   提纯  

摘要： 1成果简介:硒是支撑现代新材料发展的关键稀散元素,世界90%以上的硒从铜阳极泥中回收提取,针对铜阳极泥回收得到的粗硒渣中杂质赋存复杂、深度脱除困难等问题,提出“预处理-真空挥发-调控结晶”提纯硒思路,开展粗硒基体中典型杂质组元定向氧化调控、硒基二元合金体系气液相平衡预测以及杂质组元在硒基体中的分布调控机制等研究,成功制备出纯度为99.99%的高品质硒。

摘要： ~~

关键词： 7085铝合金   凝固疏松   组织性能   数值模拟   铸造温度   铸造速度  

摘要： 采用Pro-CAST软件完成了7085铝合金铸锭半连续铸造凝固温度场与固相场的计算优化,选择730~740℃浇注速度、33~35mm/min铸造速度与0.03~0.10MPa冷却水压获得最小的凝固液穴深度与最高的凝固冷却速度,成功实现了φ920mm直径规格7085半连续铸锭的浇注。受凝固过程固/液界面前沿驱动影响,铸锭心部区域Cu、Zn元素含量略高于成分上限,铸态组织为典型的树枝状枝晶组织,基本相为α-Al和Mg_(2)Zn_(3)相,弥散相Al_(3)Zr呈球状且多以亚稳态形式存在,沿心部-中部-边缘铸态晶粒尺寸持续减小,分别为318μm、246μm与127μm。凝固过程析出的Al_(2)Cu相、Mg_(2)Zn_(3)相、Mg_(2)Zn等粗大颗粒相受拉伸应力作用后,脱落残留在断口表面形成了数量众多的微凹坑,平均直径约为94μm且形貌为平直形,晶界处富集分布了Mg_(2)Zn_(3)颗粒相,铸态平均抗拉强度、屈服强度、断口伸长率与断面收缩率分别为419MPa、350MPa、2.2%与2.1%。

关键词： 铸造铝合金   合金元素含量   热处理规范   金相分析   铸造性能   铸造工艺   二元合金   亚共晶  

摘要： 铸造铝合金的合金元素含量较高(8wt%~25wt%),并含有足够的硅以保证铸造性能。铸造铝合金的组织、性能主要与其成分相关,同时还与铸造工艺和热处理规范有关。一、Al-Si系铸造铝合金及其金相分析常用Al-Si系铝合金中硅含量约为5wt%~13wt%,属于亚共晶和共晶型合金。其中包括简单A1-Si二元铝合金以及在A1-Si二元合金中再加入Cu、Mg、Mn、 Ni和Zn等合金元素形成复杂三元、四元等合金。为适应更高的耐磨、耐腐蚀要求,还发展了过共晶的A1-Si系合金。

关键词： 冷却速率   界面组织   元素偏析   Al   Mg   相  

摘要： 采用固/液复合铸造工艺制备了AZ91D/6061、AZ91D/Al双金属复合铸锭，研究了冷却速率对复合铸锭宏观、微观组织的影响，重点研究了冷却速率与半固态显微组织/枝晶组织界面成分分布、显微组织形态的相互关系。结果表明：镁/铝复合界面的组织构成主要有α-Mg基体、Al12Mg17相与Al3Mg2相；冷却速率对复合铸锭界面宽度及界面处形成的金属间化合物有一定的影响；随着冷却速率的增加，界面处枝晶组织变化，界面处AZ91D镁合金侧共晶结构来不及熔化，元素偏析减弱，界面层处网状结构增加，宽度变大，Al3Mg2相宽度增加，界面层的硬度增加。

标准号: GB/T 2546.1-2022

摘要： 本文件适用于所有丙烯均聚物和其他1-烯烃单体质量分数小于50%的丙烯共聚物以及上述聚合物质量分数不小于50%的共混物。本文件适用于常规为粉状、颗粒或碎粒状，未改性或经着色剂、添加剂、填料等改性的材料。本文件不适用于丙烯基橡胶。

关键词： Fe-based binary alloy   H+/D+ ion implantation   vacancy-type dislocation loop   TEM  

摘要： Reduced activation ferritic/martensitic (RAFM) steels have been considered as a family of prime candidate structural materials for fusion reactors due to low radioactivity and good resistance to irradiation swelling. Various types of defects such as dislocation loops can form in these materials during irradiation. Effects of alloying elements in iron on the formation and migration of dislocation loops have been widely investigated. However, most studies dealt with interstitial-type dislocation loops in iron alloys, while very few focused on vacancy-type dislocation loops. Previous high voltage electron microscope (HVEM) studies from the authors' group have shown that interstitial loops are fully eliminated in hydrogen-ion-implanted alpha-Fe at 500 degrees C, only vacancy loops remain and can achieve up to 100 nm in size. The addition of Ni in alpha-Fe can reduce the formation temperature of vacancy-type dislocation loops (T-c) to similar to 450 degrees C, while the addition of Cr can increase the temperature to above 600 degrees C. However, these experiments are usually difficult to perform due to the scarce resource of HVEM facilities. In this work, in-situ observations by conventional transmission electron microscope (CTEM, 200 kV) are systematically carried out on the hydrogen-ion-implanted alpha-Fe and Fe-based binary alloys (Fe-3wt.%Cr, Fe-1.4wt.%Ni and Fe-1.4wt.%Mn). The evolutions of morphology and average size of dislocation loops under different annealing temperatures are investigated. The formation temperatures of vacancy-type dislocation loops are determined from the change of average loop size with annealing temperature. The results are consistent with previous studies by HVEM. The effect of Mn atoms in alpha-Fe is similar to that of Cr atoms, which leads to T-c increase, and the addition of Ni in alpha-Fe can reduce T-c. Furthermore, the results of D thermal desorption spectrum analysis show that T-c is affected by the binding and release process of hyd