一种镍基粉末高温合金的静态再结晶行为

用EBSD和SEM等技术手段研究了热变形后的某种新型镍基粉末高温合金在不同温度下的静态再结晶行为。结果表明,镍基高温合金的静态再结晶开始温度在900℃以上,合金的显微硬度显著下降;而在组织中存在的γ’相和碳化物颗粒抑制再结晶晶粒的长大,在1100℃再结晶退火后合金的平均晶粒尺寸在约5μm。     

基于正交试验的工业挤压态AZ31镁合金预处理试验研究

运用正交试验的方法，对工业挤压态AZ3l镁合金在不同的加热温度、保温时间和冷却方式的条件下进行了预处理，研究了预处理工艺对其组织和晶粒尺寸的影响。实验表明，预处理过程中发生的静态回复与再结晶可以达到细化晶粒的目的。在预处理方案为加热温度325℃、保温时间20min、空冷的条件下，其晶粒尺寸由原始的45．4μm细化为26.3μm；晶粒尺寸随加热温度的提高及保温时间的延长均先细化后长大，而冷却方式对晶粒尺寸的影响较小。     

热处理对Ti-Mo合金组织及硬度的影响

对TiMo合金进行不同温度固溶处理,研究组织演变规律、硬度随温度的变化规律及其再结晶温度。结果表明：从750℃到820℃固溶,硬度呈现降低-升高-降低的变化规律;3%的α相含量与平均晶粒尺寸31.8μm的β晶粒混合组织形态具有硬度最小值（251.8 HV5）;合金的相变点为790～800℃;合金再结晶起始温度为760℃,完全再结晶温度为770℃。     

奥氏体再结晶区变形温度对微合金钢晶粒细化的影响

采用热模拟实验研究了奥氏体再结晶区变形温度对微合金钢晶粒细化和宏观硬度的影响。结果表明:奥氏体再结晶区变形温度显著影响钢材的显微组织。变形温度由1100℃降至1000℃,原奥氏体晶粒尺寸由60.0μm大幅度细化至34.1μm,细化了43.2%。最终获得了铁素体+珠光体组织,铁素体晶粒尺寸也实现了显著的细化,由15.5μm细化至8.8μm,细化程度达43.2%。但奥氏体再结晶区变形温度对宏观硬度的影响不大。因此,为了提高钢材,尤其是厚板的强韧性,再结晶区变形温度应适当降低。     

AZ31B镁合金板材退火工艺及晶粒尺寸模型的研究

系统地对冷轧AZ31B镁合金板材的退火工艺和退火过程中的组织变化进行了研究，试验结果表明在250～300℃下保温30～60min可以得到平均晶粒尺寸为16μm左右的细小均匀的组织。另外还研究了晶粒长大随温度、时间的变化情况。通过非线性回归分析得到了静态再结晶晶粒尺寸D与退火温度T、保温时间t的定量关系，为指导生产和进一步研究再结晶晶粒结构提供了可靠依据。     

ECAP法制备超细晶铜的再结晶行为研究

在室温下，采用ECAP技术对纯铜进行了1-10道次的挤压，使其组织大大细化，得到了均匀、细小的等轴晶，平均晶粒尺寸为0．75μm。通过对不同ECAP道次后的退火试样的硬度测量和观察组织，结果表明：随ECAP道次的增加．开始再结晶的温度降低，再结晶软化的速率增加，ECAP8道次试样在433K发生静态再结晶。     

不同热处理工艺下6111铝合金的组织及抗晶间腐蚀

采用金相显微镜、透射电镜、X射线衍射仪等研究6111铝合金经不同温度固溶、预时效后的组织和晶间腐蚀情况。结果表明，在不同温度固溶和预时效后，晶粒均发生了再结晶，部分晶粒沿着轧制方向拉长，520℃和540℃固溶后的平均晶粒尺寸为60～70μm, 560℃固溶后的平均晶粒尺寸略大于520℃和540℃,为80μm左右。520℃固溶、80℃预时效后的抗晶间腐蚀最差，腐蚀深度为191.59μm, Q相在晶界处连续分布，表面晶粒尺寸较小；540℃固溶、80℃预时效后的抗晶间腐蚀最好，腐蚀深度为59.63μm, Q相在晶界处断续分布，并未发现尺寸较小的表面晶粒。     

7075铝合金在多向大变形锻造和退火中细晶粒结构的演变

利用多向大变形锻造工业工艺和显微组织观察,研究了工业7075铝合金中细晶粒显微组织的演变。在工业生产条件下,7075铝合金基体在锻造过程中可发生完全的动态再结晶,产生出平均尺寸小于2μm的细小等轴再结晶晶粒结构,晶粒内包含高密度位错与弥散细小的第二相粒子缠结。锻件经390℃～450℃退火1h后,晶粒尺寸仍在2μm～3μm左右,这说明动态再结晶晶粒结构在静态退火期间是很稳定的。     

园林装饰用耐候钢的轧制与性能研究

研究了开轧温度、终轧温度和卷曲温度对园林装饰用耐候钢组织和耐腐蚀性能的影响,并与Q235钢进行了对比分析。结果表明,随着开轧温度的降低,耐候钢的平均晶粒尺寸逐渐降低;降低终轧温度,可以一定程度上减小耐候钢的晶粒尺寸;卷曲温度为540℃时耐候钢的晶粒尺寸为10.4μm,卷曲温度为640℃时耐候钢的晶粒尺寸为15.1μm,提高卷曲温度后耐候钢的晶粒明显粗化;开发的耐候钢的腐蚀速率和腐蚀深度都小于Q235钢,且开轧温度990℃、终轧温度840℃、卷曲温度为590℃工艺条件下耐候钢的耐腐蚀性能最好。     

形变温度对含ZrC粒子的20Mn2钢晶粒细化的影响

采用热模拟单向压缩试验，研究了含碳化锆粒子的20Mn2钢在不同温度（850～1150℃）和不同形变量（30％～80％）下的晶粒细化行为。组织分析表明，ZrC粒子起到形变核心和再结晶核心的作用，提高了奥氏体动态再结晶形核率，即使在1150℃和1050℃的高温形变状态下，晶粒也能细化至3～4μm；同时因为ZrC作为形变核心的作用，增大了奥氏体内的局域集中形变程度，使得形变诱导铁素体相变能够在较高的温度（950℃）下提前发生；并因为晶粒的细化提高了获得马氏体组织的临界冷却速度，使得各温度下的形变淬火态组织发生了由马氏体向贝氏体乃至形变诱导铁素体的演变过渡。硬度分析表明，晶粒细化及应变产生的硬化作用不仅足以抵消因马氏体或贝氏体的减少和消失带来的硬度降低，还能够进一步提高20Mn2钢的硬度值，并且晶粒细化产生的硬化幅度更大。应力应变分析表明，由于奥氏体再结晶引起了1150℃和1050℃下的形变应力下降，同时由于形变诱导铁素体相变及其再结晶降低了950℃及其以下各温度的形变应力。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.     

Bulletin of the Awards in 2013

<正>Five reviewers and 9 published articles are selected as the Excellent Rewewerand Excellent Article in 2013 respectively.Excellent Reviewers:Prof.Z ongyi Ma(Institute of Metal Research,CAS,C hina);Prof.Y ongbo Xu(Institute of Metal Research,CAS,C hina);Prof.Guangping Zhang(Institute of Metal Research,C AS,C hina);Prof.Z hendui Cui(Tianjin University,China);