稀土与mg原子半径

稀土与mg原子半径 镁合金稀土合金化的研究进展 摘要:镁合金是工程应用中最轻的金属结构材料，具有密度低、比强度高、比刚度高、减振 性高等优点，被誉为21世纪绿色工程金属结构材料。稀土元素由于具有独特的核外电子结 构，作为一种重要的合金化元素，在冶金、材料领域起着独特的作用，例如净化合金熔体， 细化合金组织，提高合金力学性能和耐腐蚀性能等。综述了稀土在镁合金中的行为，介绍了 一系列重要的稀土元素对镁合金的组织和力学性能的影响，并对稀土镁合金发展提出一些展 望。 关键词:稀土;镁合金;组织;性能 Abstract:Magnesium alloy is the lightest metal structure material，which has low density and high strength，high stiffness ratio and high shock absorption(It is known as green metallic structural materials in the 21st century(Rare earth elements as an important alloying element in metallurgy plays a unique role in this field，such as purification of molten alloy，refinement of microstructure，improvement of mechanicaI properties and corrosion resistance，and so on(Behavior of rare-earth in magnesium alloy is summarized in this paper(Effects of a series of important rare earth on microstructure and mechanical properties of magnesium alloys is also introduced(Some outlook of rare-earth magnesium alloy is made( Rare-earth;Magnesium Alloy;Microstructure;Property Key words: 镁合金是继钢铁和铝合金之后发展起来的第三类金属结构材料，被誉为“21世纪绿 色工程材料”，也是目前在实际应用中最轻的金属结构材料。镁合金具有比强度高、比 刚度高、阻尼减振性能好以及优异的铸造、切削加工性能和易回收等优点，在航空航天、 [1,2]国防军事等领域具有极其重要的应用价值。中国是镁资源大国，镁资源储量居世界第 一，随着很多金属矿产资源的日益枯竭，镁合金日益受到广泛关注。随着我国经济和工 业的不断增强发展，必将加大在镁及镁合金方面研究和应用的投入，镁合金必将有更为广阔 的前景和发展空间。 稀土元素由于具有独特的核外电子结构，作为一种重要的合金化元素，在冶金、材料领 域起着独特的作用。例如净化合金熔体，细化合金组织，提高合金力学性能和耐腐蚀性能等 [3]。作为合金化元素或微合金化元素，稀土已经被广泛应用于钢铁及有色金属合金中。此外， 稀土加入镁合金中，促进合金表面氧化膜由疏松变为致密，降低合金在液态和固态下的氧化 [4]倾向，从而提升传统镁合金耐蚀、耐磨等性能。 [1] 师昌绪，李恒德，王淀佐等，加速我国金属镁工业发展的[J]，材料导报，15(4)(2001)5. [2] Y.Kojima, T.Aizawa, S.Kamada etc. Progressive Steps in the Platform Science and Technology for Advanced Magensium Alloys, Materials Science Forum[J], 2003(3).:419-422 [3] 余琨,黎文献,王日初,等.稀土Ce和Nd对AZ31镁合金耐蚀性能的影响[J].材料保护,2007,40(11):6-10. [4] Wenjuan Liu,Fahe Cao,Linrong Chang.Effect of rare earth element Ce and La on corrosion behavior of AM60 magnesiumalloy[J](Corrosion Science，2009(51):1334—1343( the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 1. 稀土合金化的微观机理 稀土元素位于元素周期表第三副族，其结构特点是原子的最外层电子结构相同，都是2个电子，次外层电子结构相似，倒数第三层4f轨道上的电子数从0-14各不相同。稀土原子半径大，极易失掉外层两个S电子和次外层5d 一个电子或4f 层一个电子而成3价离子，某些稀土元素也能呈2价或4价态， ,1,具有很高的化学活性，与O、S 等元素有较强的结合力。由于合金组成成分决定显微组织结构及 ,2,其宏观性能，一般而言，合金成分设计主要考虑四个方面因素: (1)晶体结构因素。根据Hume-Rhthery Rules 固溶准则，金属结构相同、原子尺寸和电化学特征相近的元素，才能形成无限固溶体。镁合金与稀土元素皆具有密排六方晶体结构(hcp)，使得稀土元素在镁合金中固溶度较大，几乎所有的稀土元素对α-Mg都有较好的固溶强化作用。 (2)原子尺寸因素。溶质和溶剂原子大小差值在15%以内才形成无限固溶体。大部分稀土元素与 [3]镁的原子尺寸半径相差在?15%围内(见图1)，各种稀土元素在镁中的溶解度不同，增加的顺序为 La、混合稀土、Ce、Pr、Nd。稀土元素可增强镁合金原子间的结合力，减少原子扩散速度。 (3)电负性因素。溶质元素与溶剂元素之间电负性相差越大，生成的化合物越稳定。Darken-Gurry理论认为，电负性差值大于7 8 & 的元素不易形成固溶体。表" 为稀土元素在镁中的固溶度与原子半 ,#,径差、电负性的关系。 (4)原子价因素。溶质和溶剂的原子价相差越大，则溶解度越小。 ,2, 刘光华.稀土固体材料学,M,. 北京:机械工业出版社，,1997 ,3, 张津，章宗和.镁合金及应用,M,. 北京:化学工业出版社，2004 ,4, 郭旭涛，李培杰，刘树勋，等. 稀土耐热镁合金发展现状及展望,G,7.铸造，2002,51(2):68-71 ,5, 余琨. 稀土变形镁合金组织性能及加工工艺研究,D,.长沙:中南大学博士论文，2002: 14-15 the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 2. 稀土的阻燃作用 由于镁与氧极易发生反应，因此镁合金在熔炼和浇注过程中易氧化燃烧。镁与氧反应生成的表面MgO膜，致密度系数αMg<1，疏松多孔，不能有效阻止氧穿透该氧化膜;且MgO的导热系数小，不利于热量的扩散，会加剧镁的氧化和燃烧。稀土元素加入镁合金后，与氧发生反应或与MgO中氧发生置换反应生成稀土氧化物RE2O3，该稀土氧化物的致密度系数α>l，能够有效阻止氧穿透氧化膜与镁发生反应。 刘平平等研究了Ca、Y对ZK60镁合金阻燃性能的影响。ZK60镁合金中添加Ca、Y阻燃作用明显，相对于不加Ca、Y时。含1(62,Ca合金燃点可提高171?。含2(95,Y燃点可提高253?。Ca、Y复合加入时(1(96Y1(05Ca)燃点达到最高值，在845?保温30min未燃烧。含Ca镁合金氧化膜分为三层，表层主要为MgO和ZnO，中间层含大量O、Mg和少量Ca，最内层含大量O、Mg和较多Ca，由三层氧化物组成的复杂氧化膜组成。含Y镁the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 合金的氧化膜主要由MgO、Y203和ZnO组成，由于Y203和ZnO提高了氧化膜的致密度系数，从而提高了合金的燃点。Ca、Y复合加人时，氧化膜表面主要为MgO和Y203，氧化膜内含大量的O、Mg、Ca和少量的Y和Zn(由于Ca的第三元素效应使得合金燃点大幅提高。目前阻燃镁合金理论研究大多停留在对含钙、含铍、含锌和某些稀土阻燃镁合金的研究，对于含Y阻燃镁合金的研究比较少，今后可加强Y在阻燃镁合金中的应用。 刘平平(郝启堂。Ca、Y对ZK60镁合金阻燃性能的影响材料热处理技术2009， 38，( 38-42 3. 稀土对镁合金组织的影响 2.1稀土对镁合金铸态组织的影响 稀土的加入会明显细化镁合金晶粒内部的微观组织.合金的铸态微观组织取决于凝固过程，合金的凝固过程通常是由表面向中心推进，晶粒的最终形貌(等轴或柱状)取决于凝固界面前沿液体条件。镁合金中加入一定量稀土，由于RE在合金中的固溶度极低，平衡分配系数k<<1[14]稀土易在固/液界面前沿富集,增大了合金的成分过冷而使分枝过程加剧,二次枝晶增多!最终使枝晶间距减小,使晶粒内部组织得到细化。 [8]黎文献等研究了Ce对Mg-Al镁合金晶粒尺寸的影响，在Mg-Al系AZ31合金中添加微量稀土元素Ce，可明显细化合金晶粒，当Ce的加入量为了0(8,时，晶粒细化效果最好，由未细化前的约300 u m下降到约20,40μm。Ce在镁及镁合金中的细化作用是由于稀途元素在凝固过程中固,液界面前沿富集而引起成分过冷，过冷区形成新的形核带而形成细等轴晶。凝固过程中溶质再分配造成固液界面前沿成分过冷度增大是稀土元素细化镁及镁合金的主要机理。此外，稀土在固,液界面前沿的富集使其起到阻碍α-Mg晶粒长大的作用，进一步促进了晶粒的细化。 S H Wang.H P Zhou.Y P Kang The influence of rare earth elements on microstructures and properties of 8061 aluminum alloy vacuum-brazed joints [J]. Journal of Alloys and Compounds, 2003,(352):79-83. 2.2稀土对镁合金固溶和时效处理态组织的影响 4. 稀土对镁合金力学性能的影响 4.1细晶强化 稀土元素在固液界面前沿富集引起成分过冷, 过冷区形成新的形核带而形成细等轴晶, -Mg晶粒长大的作用, 进一步促进了晶粒的细化。根据此外稀土的富集使其起到阻碍α Hall-Petch 公式, 合金的强度随晶粒尺寸的细化而增加, 并且相对体心立方和面心立方晶体而言, 晶粒尺寸对密排六方金属强度影响更大, 因此镁合金晶粒细化产生的强化效果极为显the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 著。 [10]陈芙蓉等研究了Ce对AZ91D镁合金组织和力学性能的影响。Ce加入到镁合金组织后，细化合金组织起到细晶强化作用;使网状的β相细小并弥散分布于晶界上;同时在晶界形成弥散分布的Al4Ce化合物起到第二相强化作用，当Ce含量为0(69,时，含金的抗拉强度、屈服强度、伸长率及硬度分刺比AZ91D镁合金提高15(8,、8.7,、140,及15(7,，其综合力学性能达到最佳。 3.2 固溶强化 大部分稀土元素在镁中具有较高的固溶度, 当稀土元素固溶于镁基体时，由于稀土元素与镁的原子半径和弹性模量的差异，使镁基体产生点阵畸变。由此产生的应力将阻碍位错运动，从而使镁基体得到强化。稀土元素固溶强化的作用主要是减慢原子扩散速率, 阻碍位错运动, 从而强化基体, 提高合金的强度和高温蠕变性能。 [6 ] 黎文献, 余 琨, 张世军. 稀土对镁及Mg2Al 合金晶粒细化的研究[A] . 第三届有色合金及特种铸造国际会议论文集[C] . 上海: 2003. 69. Yan Jingli等[15]研究了Mg–2wt.%Nd镁合金的蠕变性能。在150至250?C，应力30至110 Mpa的条件下，在固溶强化和析出强化的作用下合金表现出良好的抗蠕变性能。在蠕变过程中有细小的沉淀物析出，这对限制位错的运动起到了重要作用。 3.3晶界强化 通过向镁合金中添加稀土,可以在晶界处形成富Mg-RE相和Al-RE相，这些相的熔点很高,热稳定性很好，它们的存在能阻止高温下镁合金晶粒的长大和晶界的滑移，起到晶界强化的作用，从而明显提高镁合金高温性能和抗蠕变能力。 Z.L. Ning等研究了Nd对Mg–0.3Zn–0.32Zr 合金微观结构和力学性能的影响。 当合金中Nd的加入量由0.21% 逐渐增加至 2.65%时，合金的的晶粒尺寸由120μm减小至60μm，同时晶粒形态从六面体结构转变为类似玫瑰状结构。当Nd的加入量小于0.84% 时，Nd能够完全溶入镁基体中，铸锭中只有单相的α-Mg，当Nd的加入量超过1.62%，通过X射线衍射仪测试发现在晶界和晶界三角区有金属间化合物MgNd生成。晶粒和晶界中的MgNd1212相能够锁定晶界，减少晶界限滑移和位错滑移，能够明显改善镁合金高温下的抗拉强度，和屈服强度，同时伸长率稍有降低。 [13]Li Mingzhao等利用金相显微镜，SEM, EDS, XRD等手段研究了Nd对AZ31镁合金微观结构和力学性能。结果表明:在AZ31镁合金中加入微量的Nd能够在晶界和α-Mg相中生成金属间化合物AlNd 和 MgNd ，Nd的吸收率高达95%，能够明显改善AZ31镁合212 金的微观结构和提高合金的力学性能。在AZ31镁合金中加入0.6wt%，抗拉强度达到245 MPa, 屈服强度为171 Mpa 延伸率为 9%。 the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 5. 稀土对镁合金耐蚀性的影响 镁合金在环境介质中表面都会形成一层很薄的氧化膜，这种多孔状的氧化膜不能有效阻止环境介质，特别是氧化性和腐蚀性介质对镁合金基体的腐蚀，影响到镁合金的使用性能，在镁合金中添加稀土元素，可有效改变合金腐蚀层结构,强化阴极相控制，影响合金腐蚀的电化学过程，从而提高镁合金的耐蚀性能。 段汉桥王立世蔡启舟等稀土对AZ91镁合金耐腐蚀性能的影响[J].中国机械工程 ,2003,14(20):1789-1792 [18]吴国华等研究了稀土La对AZ91D镁合金在NaCl溶液中耐蚀性的影响，AZ9lD合金中加入1,La(质量分数)后，不但形成了条状的A1La相和块状的AlLaMn相，而且在粗11384大p相(MgAl)周围形成了许多细小的层片状β相，并使β相进一步网状化(这些细小的l7l2 层片状p相明显阻碍了腐蚀的扩展，提高了AZ91D镁合金的耐蚀性(条状的AlLa相和块113状的AlLaMn相都属于阴极耐蚀相(其中AlLa相由于较小的阴极面积，对加速其周围镁84113 基体的腐蚀不起明显作用;而块状的AlLaMn相阴极面积较大，与基体构成微电偶腐蚀，84 加速了基体的腐蚀( [11]杨洁等研究了Ce对AZ91镁合金微观组织及耐蚀性的影响，结果表明:Ce细化了合金的微观组织，使β—MgAl相变得断续、弥散，成分分布更为均匀，生成了ACe相及171214 Ce—Fe的金属间化合物;稀土Ce使合金在3(5,NaCl溶液中的自腐蚀电Mg—Al—Mn— 位升高，与Al、O生成了不连续的保护性氧化膜，提高了合金的耐腐蚀性能. 4.1 稀土改变了镁合金腐蚀层的结构 4.2 稀土强化了镁合金的阴极相控制 4.3 稀土影响镁合金腐蚀的电化学过程 6. 结束语 我国有丰富的稀土和镁资源，是稀土和镁资源储备、生产、出口的第一大国。因此，研究开发稀土镁合金在我国具有独特优势，合理利用稀土资源，开发含稀土的高强、耐热、耐蚀性能镁合金，不但能进一步增加镁合金材料在汽车工业、通讯电子业等行业领域中的应用，也可促进镁合金材料在新领域中的进一步开发和利用，也为稀土材料的应用开辟出十分广阔的领域。为扩大稀土镁合金在工业领域中的应用，还需要解决以下几个关键问题:(1)开发新型的稀土镁合金，通过添加混合稀土、稀土与微量元素(Ca，Sb等)，提高镁合金的性能，进一步降低生产成本;(2)研究稀土镁合金的耐蚀机理，寻找经济可行的表面处理新工艺，the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were 延长使用寿命。(3)进一步稀土对合金宏观和微观组织及各种性能影响的机理，稀土加入方 式和熔炼质量控制方法。 the provisions of Hunan province safety production supervision and management responsibilities > (Hunan Zhengban made 2013 No. 4), resolutely implement the safety production of the party with responsibility, a pair of responsibility. "Two is issued safety production administration and inspection to promote the responsibilities bear safety production supervision departments strictly and effectively assumed responsibility. The three is the establishment of enterprise production safety hidden With self correction self reporting system, promote the enterprises to implement the main responsibility for production safety. The four is the introduction of strengthening county safety production supervision ability construction work, promote safe production responsibility to the grassroots. 3, strict accountability and target management. Adhere to the "who is in charge, who is responsible for the pipe industry must pipes, pipe production and management must control safety management business must be safe" principle, the implementation of safe production supervision and stagnation to cure. "The leadership responsible system. Production safety of key towns, key enterprises and key problems, by the township government and the Department responsible for the stagnation led the lump sum, to tackle tough. To further increase the production safety index assessment, strict implementation of safe production of "one vote veto" award and recognition system, strengthen production safety incentive mechanism (four). Adhere to the political principles against unwholesome tendencies existence of the problem is not strict internal supervision. Over the years, the global leadership team members do not have any illegal and other bad records, but there are still not strict, the implementation does not survive the problem. A few leading cadres not strictly in accordance with the county Party committee, county government On strengthening style construction requirements and style construction safety supervision system of "ten prohibitions", to solve the people most concerned, the most direct, the most realistic problem of production safety as the starting point and goal of all work, to strengthen internal supervision on the way, in the perfect power control mechanism on "let things drift", get free in the political norms of leading cadres, some involving major principle problems of ambiguous attitude, major issues issues of right and wrong, it cannot stand up bravely, face to face, resolute struggle and discredit the views of the party in 2012. The style of the big consolidation activities, cadres and workers 6 people were