CRYSTAL STRUCTURE OF A LONG－PERIOD ORDERED PHASE IN Fe－C MARTENSITE AND COMPUTER SIMULATION OF ITS ELECTRON DIFFRACTION PATTERNS

ＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＯＦＡＬＯＮＧ－ＰＥＲＩＯＤＯＲＤＥＲＥＤＰＨＡＳＥＩＮＦｅ－ＣＭＡＲＴＥＮＳＩＴＥＡＮＤＣＯＭＰＵＴＥＲＳＩＭＵＬＡＴＩＯＮＯＦＩＴＳＥＬＥＣＴＲＯＮＤＩＦＦＲＡＣＴＩＯＮＰＡＴＴＥＲＮＳＲＥＮＸｉａｏｂｉｎｇ；ＷＡ...     

EFFECT OF MICROSTRUCTURE ON FATIGUE CRACK INITIATION OF SHOT PEENED COPPER AND BRASS

ＥＦＦＥＣＴＯＦＭＩＣＲＯＳＴＲＵＣＴＵＲＥＯＮＦＡＴＩＧＵＥＣＲＡＣＫＩＮＩＴＩＡＴＩＯＮＯＦＳＨＯＴＰＥＥＮＥＤＣＯＰＰＥＲＡＮＤＢＲＡＳＳＫ．Ｗ．Ｘｕ;Ｎ．Ｓ．ＨｕａｎｄＪ．Ｗ．Ｈｅ（Ｓｔａｔｅ－ＫｅｙＬａｂｏｒａｔｏｒｙｆｏｒＭｅｃｈａｎｉｃ...     

MICROSTRUCTURES AND PROPERTIES OF MOLYBDENUM WIRE DOPED WITH LANTHANUM OXIDE

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＭＯＬＹＢＤＥＮＵＭＷＩＲＥＤＯＰＥＤＷＩＴＨＬＡＮＴＨＡＮＵＭＯＸＩＤＥＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＭＯＬＹＢＤＥＮＵＭＷＩＲＥＤＯＰＥＤＷＩＴＨＬＡＮＴＨ...     

NEW METHODS FOR CALCULATING ACTIVITIES OF COMPONENTS FROM PHASE DIAGRAMS IN BINARY PERITECTIC SYSTEMS

ＮＥＷＭＥＴＨＯＤＳＦＯＲＣＡＬＣＵＬＡＴＩＮＧＡＣＴＩＶＩＴＩＥＳＯＦＣＯＭＰＯＮＥＮＴＳＦＲＯＭＰＨＡＳＥＤＩＡＧＲＡＭＳＩＮＢＩＮＡＲＹＰＥＲＩＴＥＣＴＩＣＳＹＳＴＥＭＳ①ＺｈａｎｇＹｏｎｇｊｕｎＨｕｎａｎＳｕｐｅｒｉｏｒＴｅｃｈＭａｔｅｒｉ...     

MODELING OF SUPERPLASTIC FORMING PROCESS FOR ALUMINUM ALLOYS WITH STRAIN HARDENING EFFECT

ＭＯＤＥＬＩＮＧＯＦＳＵＰＥＲＰＬＡＳＴＩＣＦＯＲＭＩＮＧＰＲＯＣＥＳＳＦＯＲＡＬＵＭＩＮＵＭＡＬＬＯＹＳＷＩＴＨＳＴＲＡＩＮＨＡＲＤＥＮＩＮＧＥＦＦＥＣＴＹ．Ｎ．ＫｗｏｎａｎｄＹ．－Ｗ．Ｃｈａｎｇ（ＣｅｎｔｅｒｆｏｒＡｄｖａｎｃｅｄＡｅｒｏｓｐａｃ...     

INTERACTION OF PARTICLES WITH A SOLIDIFIED INTERFACE DURING SOLIDIFICATION OF METAL MATRIX COMPOSITE REINFORCED WITH PARTICLES

ＩＮＴＥＲＡＣＴＩＯＮＯＦＰＡＲＴＩＣＬＥＳＷＩＴＨＡＳＯＬＩＤＩＦＩＥＤＩＮＴＥＲＦＡＣＥＤＵＲＩＮＧＳＯＬＩＤＩＦＩＣＡＴＩＯＮＯＦＭＥＴＡＬＭＡＴＲＩＸＣＯＭＰＯＳＩＴＥＲＥＩＮＦＯＲＣＥＤＷＩＴＨＰＡＲＴＩＣＬＥＳＣＨＵＳｈｕａｎｇｊｉｅ;Ｗ...     

1996 SHANGHAI INTERNATIONAL CONFERENCE ON QUALITY ASSURANCE IN MANUFACTURE OF WELDED STRUCTURES

１９９６ＳＨＡＮＧＨＡＩＩＮＴＥＲＮＡＴＩＯＮＡＬＣＯＮＦＥＲＥＮＣＥＯＮＱＵＡＬＩＴＹＡＳＳＵＲＡＮＣＥＩＮＭＡＮＵＦＡＣＴＵＲＥＯＦＷＥＬＤＥＤＳＴＲＵＣＴＵＲＥＳ￥（ＸｕＱｉｎｇ）ＳｈａｌｌｇｈａｉｉｎｔｅｒｎａｔｉｏｎａｌＣｏｎｆｃｒｃｎｃｃ...     

EFFECT OF MILLING INTENSITY ON STRUCTURAL CHANGES OF MIXED Al－Fe－Ni POWDERS IN MECHANICAL ALLOYING PROCESS

ＥＦＦＥＣＴＯＦＭＩＬＬＩＮＧＩＮＴＥＮＳＩＴＹＯＮＳＴＲＵＣＴＵＲＡＬＣＨＡＮＧＥＳＯＦＭＩＸＥＤＡｌ－Ｆｅ－ＮｉＰＯＷＤＥＲＳＩＮＭＥＣＨＡＮＩＣＡＬＡＬＬＯＹＩＮＧＰＲＯＣＥＳＳ￥ＬｉｕＺｕｙａｎ；ＬｉａｎｇＧｕｏｘｉａｎ；ＷａｎｇＥｒｄｅ（Ｓ...     

INFLUENCES OF TRACE ADDITIONS OF STRONTIUM AND PHOSPHORUS ON ELECTRICAL RESISTIVITY AND VISCOSITY OF LIQUID Al-Si ALLOYS

ＩＮＦＬＵＥＮＣＥＳＯＦＴＲＡＣＥＡＤＤＩＴＩＯＮＳＯＦＳＴＲＯＮＴＩＵＭＡＮＤＰＨＯＳＰＨＯＲＵＳＯＮＥＬＥＣＴＲＩＣＡＬＲＥＳＩＳＴＩＶＩＴＹＡＮＤＶＩＳＣＯＳＩＴＹＯＦＬＩＱＵＩＤＡｌＳｉＡＬＬＯＹＳ①ＧｕｉＭａｎｃｈａｎｇ，ＪｉａＪｕｎ，...     

STRAIN INDUCED STRUCTURAL TRANSITION OF INTERFACES AND TWINS IN A HOT－DEFORMED DUAL－PHASE TIAL ALLOY

ＳＴＲＡＩＮＩＮＤＵＣＥＤＳＴＲＵＣＴＵＲＡＬＴＲＡＮＳＩＴＩＯＮＯＦＩＮＴＥＲＦＡＣＥＳＡＮＤＴＷＩＮＳＩＮＡＨＯＴ－ＤＥＦＯＲＭＥＤＤＵＡＬ－ＰＨＡＳＥＴＩＡＬＡＬＬＯＹＣＨＥＮＧｕｏＦｉａｎｇ；ＷＡＮＧＪｉｎｇｕｏ；ＺＨＡＮＧＬｉｃｈｕｎａｎｄ...     

硅合金钢淬火组织中残留奥氏体的力学稳定性与力学性能

对含Si合金钢两相(马氏体-M,贝氏体-B)区系列等温淬火显微组织中残留奥氏体稳定性进行了研究。结果表明,在下贝氏体区等温淬火可获得准(无碳化物)贝氏体(BF AB)组织,合理的回火工艺可使显微组织中残留奥氏体减少到适量,增加残留奥氏体中的C含量,降低Ms、Md点温度和提高其力学稳定性,从而达到最佳强韧性配合。     

贝氏体-马氏体钢板的组织与性能

研究了贝氏体-马氏体耐磨钢板的组织及力学性能。结果表明，在低碳贝氏体钢基础上，通过加入一定量的硅元素，利用其在贝氏体组织转变过程中抑制碳化物析出的作用，得到由非等轴铁素体加马氏体和残留奥氏体(M-A)岛或由板条状铁素体及其板条间残留奥氏体(Ar)膜组成的贝氏体一马氏体组织，因此其性能既具有高强度、高硬度，又具有较高的低温冲击韧度。     

800 MPa级高强钢焊缝金属热处理组织与性能

在10Ni5CrMoV高强结构钢焊接中,为了获得良好的强韧性匹配,焊后需要进行热处理来改善焊缝金属的组织和性能.试验采用富氩气体保护焊焊接10Ni5CrMoV钢,分析了不同调质热处理工艺下焊缝组织、性能的变化规律.结果表明,焊缝金属焊态的组织主要是贝氏体、少量马氏体和残余奥氏体组织,调质热处理后焊缝组织主要为回火马氏体,随着回火温度的升高,焊缝中残余奥氏体减少,马氏体中碳化物析出长大并有球化趋势.调质态焊缝金属的强度随着回火温度的升高而逐渐降低,而韧性随着回火温度的升高而显著提高.     

Effect of Retained Austenite on Properties of Austempered Ductile Iron

Austempered ductile iron (ADI) exhibits a favourable combination of strength and toughness, and has been used as a substitute for quench-tempered or carburise-quenched steel. A characteristic feature of bainite transformation of cast iron, as opposed to carbon steel, is that precipitation of carbide is suppressed by the high concentration of silicon. Thus, a favourable structure, consisting of bainitic ferrite and retained austenite without carbide, can be provided by the optimum austempering treatment. Such microstructure and the mechanical properties of the iron are significantly affected by the conditions of the austempering treatment and the chemical composition. In this study, several grades of ductile iron were austempered under various conditions. The relationship between the impact strength, the quantity of retained austenite and the isothermal transformation curve was investigated. The stability of the retained austenite is considered important, because ADI contains a large amount of retained austenite which contributes to the improvement of ductility and toughness and which may transform to martensite when held at low temperature or subjected to stress. In this study, the stability of the retained austenite at low temperatures was examined by holding or stressing to establish the relations between transformation and temperature, stress and strain.

When the austempering time is short, the untransformed austenite partially transforms to martensite during air cooling, due to the lower carbon content, resulting in lower impact strength. As the austempering time increases, the untransformed austenite is stabilised by carbon-enrichment and there is little transformation to martensite, resulting in a large amount of retained austenite and higher impact strength. When the austempering time becomes much longer, the carbon-enriched austenite decomposes, presumably to bainitic ferrite and carbide, decreasing impact strength. In increasing the silicon content, precipitation of carbide in bainite is suppressed and both the maximum impact value and the content of retained austenite increase. The decreasing rates after the maxima through an additional isothermal holding becomes smaller.

By holding at temperatures down to –40°C, the decrease in retained austenite and the increase in hardness are both small. The retained austenite is stable under stress lower than that required to cause plastic deformation. Compressive stress hinders the martensitic transformation, because the transformation is accompanied by volume expansion.     

预相变马氏体对超级贝氏体钢组织热稳定性的影响

为明确超级贝氏体组织失稳机制以及探索提高超级贝氏体钢中残余奥氏体热稳定性的方法,通过预相变马氏体工艺,即在等温贝氏体相变前引入预相变马氏体,制备了中碳超级贝氏体钢。对比分析了回火前后中碳超级贝氏体钢显微组织和力学性能的变化,研究了预相变马氏体对中碳超级贝氏体钢中贝氏体组织及残余奥氏体热稳定性的影响。结果表明：预相变马氏体的存在能够细化贝氏体铁素体板条,提高残余奥氏体含量和热稳定性。预相变马氏体的引入及其对超级贝氏体组织的细化作用使得试验钢的屈服强度超过1 000 MPa,伸长率大于20%;300～600℃回火1 h后,高碳薄膜状残余奥氏体首先发生分解,形成细小的碳化物,然后贝氏体铁素体板条发生回复和再结晶,形成沿原板条方向的铁素体晶粒;600℃回火后试验钢的屈服强度仍与回火前相当,主要是预相变马氏体周围的薄膜状残余奥氏体未发生明显分解,能够抑制相邻贝氏体铁素体板条的回复。     

高硅铸钢残余奥氏体分布形态及其对力学性能的影响

采用透射电子显微镜(TEM)对高硅铸钢等温淬火热处理后的显微组织以及残余奥氏体分布形态进行了研究,对等温淬火组织中残余奥氏体量进行了测定.结果表明,残余奥氏体呈薄膜状及块状两种分布形态.薄膜状分布的残余奥氏体与贝氏体铁素体间的位向符合K-S关系,对钢的综合力学性能特别是韧性有积极的作用;而呈块状分布的残余奥氏体,由于其机械稳定性差,对钢的各项力学性能有不利的影响.要获得具有优异综合力学性能的高硅铸钢,薄膜状残余奥氏体与块状残余奥氏体体积分数量的比值Vγ-F/Vγ-B要大于1.0.     

淬火工艺对耐磨钢NM400组织性能的影响

采用微Nb、B,加少量Cr成分体系,研究不同离/在线淬火工艺对NM400钢显微组织和力学性能的影响,通过光学显微镜、SEM和TEM观察,分析离/在线淬火工艺对马氏体精细结构的演变规律。结果表明:在线淬火工艺马氏体块更细小,大角度晶界比例大,保留轧制奥氏体变形位错等缺陷,为碳化物在回火中析出提供位置,使析出物分布更弥散,同时拥有马氏体-下贝氏体复相组织,提高了钢的硬度、强度和韧性。     

热输入对800MPa级超厚板窄间隙焊缝金属组织和性能的影响

采用三种热输入进行超厚板窄间隙熔化极气体保护焊,借助金相显微镜、扫描电子显微镜及附带EDS系统和透射电子显微镜研究了热输入对焊缝金属组织和性能的影响.结果表明,三种热输入焊缝金属组织主要由板条马氏体、无碳化物贝氏体、M-A组元和残余奥氏体组成.随着焊接热输入的增加,焊缝组织中马氏体含量减少;也使无碳化物贝氏体形核率降低,造成无碳化物贝氏体粗化.并且当贝氏体相变时热输入的增加使碳原子扩散距离变远,促使残余奥氏体形状由膜状向块状转变.另外随着热输入的增加,焊缝金属强度下降,而冲击韧性对热输入不敏感.     

冷却介质对新型贝氏体铸钢组织和性能的影响

研究了不同冷却介质对新型贝氏体铸钢组织和力学性能的影响：结果表明：ZG30CrMn2Si2Mo铸钢奥氏钵化后，空冷获得的组织是由贝氏体铁素体和残余奥氏钵组成的新型贝氏体组织，油冷、水玻璃冷和水冷后获得的组织是由马氏体、贝氏体和残余奥氏体组成的复相组织；随介质冷却能力的增加，有利于提ZG30CrMn2Si2Mo铸钢的综合性能，水冷后可获得较好的强韧性配合。分析了冷却介质对性能影响的原因。     

18CrMn2SiMo钢齿轮渗碳后的组织与性能

研究了18CrMn2SiMo齿轮用钢的组织、力学性能及渗碳性能。结果表明,18CrMn2SiMo钢渗碳后空冷低温回火,渗层的组织为高碳马氏体和奥氏体,非渗碳区为贝氏体铁素体和奥氏体。用18CrMn2SiMo钢制造的齿轮具有优异的渗碳性能,并具有良好的强韧性配合。介绍了18CrMn2SiMo钢在重载齿轮方面的应用。