工业纯钛牌号的对照和选材

工业纯钛是指含有少量氧、氮、碳及铁和其他残余杂质的致密金属钛.根据其杂质元素含量的不同,特别是对改变钛的特性影响较大的氧、氮、铁元素的不同而分为不同的级别.本文力图通过对我国工业纯钛的生产和标准发展的介绍.明确工业纯钛牌号的国内外对照,从而指导工业纯钛的应用和选材.     

热挤压和旋锻粉末冶金纯钛的组织和力学性能

采用粉末冶金技术结合热挤压和旋锻工艺制备纯钛棒,利用万能试验机、维氏显微硬度仪、金相显微镜、高精度多功能密度计等设备测试纯钛棒的屈服强度、维氏硬度、显微组织和相对密度,研究了纯钛棒的制备工艺及其微观组织结构对材料力学性能的影响。研究表明,利用粉末冶金技术结合热挤压和旋锻工艺制备的纯钛棒屈服强度是880 MPa,均匀延伸率是4.06%,在拉伸变形过程中发生韧性断裂。纯钛棒显微组织为等轴状的细晶粒组织,平均晶粒尺寸约1μm,组织分布均匀,无明显裂纹和缺陷,有较高的相对密度。     

镁热法海绵钛生产中杂质元素来源浅析

海绵钛作为一种优质金属被广泛应用于航空航天等各个领域,其中的杂质含量直接影响产品品质,海绵钛中的主要杂质有铁、氧、氯、碳、氮、硅等,文章主要对镁热法海绵钛生产过程中部分杂质的来源进行了分析。     

工业纯钛制品在强腐蚀介质下的经济性分析

工业纯钛(TA2)在通常的情况下是稳定的,但在330℃以上的高温下很活泼,易与氮、氧、硫等化合生成氮化物、氧化物、硫化物,使钛材料脆化和降低塑性.在高温下,还会与碳作用生成熔点很高(3100℃)硬度很大的碳化钛TiC,因此冶炼钛时不能用碳作还原剂.     

生物医用Ti6Al4V合金注射成形研究北大核心

利用PEG基粘结剂体系和气雾化球形Ti6Al4V合金粉制备了成分均匀、流变性能及热性能稳定的注射料,并进行烧结。通过工艺参数调控,1 320℃下保温3 h的烧结试样相对密度97.6%,极限抗拉强度900 MPa,屈服强度867 MPa,伸长率为12%,力学性能整体满足ASTM F2885-11标准要求。高真空烧结条件加速了烧结件的致密化过程,而且能够有效降低氧、氮等杂质元素的含量,除氧元素质量分数(0.229%)略高于标准值(<0.200%)外,其他杂质元素含量均满足ASTMF2885-11标准。     

铝稀土合金的制取和应用

前言众所周知,纯铝轻而有银白色光泽,不生锈,是热和电的良导体。具有一定的强度,硬度和延展性。易加工,可以制成各种部件和制品应用于工业,农业,国防及日常生活日用品中。但是电解生产出来的普铝含有少量铁、硅、氧、氟等杂质。在加工熔炼     

钢中的微量钛

钛是极为活泼的元素,与氮、碳都有极强的亲和力,和氧及硫的亲和力也大于铁。从微合金化钢中常用的合金元素来看,钛与碳、氮、氧、硫之间的亲和力均大于钒和铌,与氧和硫的亲和力虽不及稀土,但与碳和氮的亲和力却大于稀土。由此便     

硅中碳的行为与影响

碳是硅中与氧密切相关的重要杂质,现在氧已成为影响器件性能及成品率的关键因素,碳的重要性也日益明显。然而,目前对碳的了解却远不如氧。本文将叙述硅中碳的来源与分布(包括轴向与径方分布、碳条纹及碳沉淀等),碳对材料性能(如NTD硅的退火行为、热施主形成、硅中金扩散、原生单晶中微缺陷等),器件性能(包括功率器件、低压器件及集成电路)的影响等。最后叙述碳与氧沉淀的关系。     

稀土元素对GW157高比重合金力学性能的影响

为改善ＧＷ１５７高比重合金的塑性和韧性，研究了添加稀土元素Ｌａ对合金力学性能的影响。结果表明，添加适量的Ｌａ可以显著提高合金的力学性能，其主要原因是Ｌａ的加入改变了杂质元素氧的存在与分布状态，使氧由界面偏聚转变为稳定的氧化物，减小了它在钨－粘结相的界面偏聚，从而提高了两相界面的结合强度，进而提高了合金性能。     

添加Nd对注射成形钛合金中氧的分布及力学性能的影响

采用粉末注射成形工艺制备含钕的钛合金TixNd(x为Nd的质量分数,%),采用金相显微镜、扫描电镜、电子探针以及硬度和力学性能测试等分析手段,研究钕对注射成形钛合金中氧的分布及力学性能的影响,并分析钕的最佳添加量。结果表明:随钕含量增加,合金的密度和伸长率先增加后降低,其中Ti15Nd的性能最优异,其相对密度为98.2%,强度和伸长率分别达到634 MPa和6.5%,比纯钛分别提高248 MPa和6.5%。纯钛的断裂面呈现解理断裂特征,而Ti15Nd为延性断裂。添加钕能提高钛合金的致密度,并且钕能吸收周围钛基体中的氧原子形成氧化钕,调节TixNd合金中氧的分布,从而有效提高合金的强度和韧性。计算证明氧化钛的分解和氧化钕的形成在热力学上是可行的。建立Ti-Nd扩散模型,考虑钕的蒸发和氧化等因素,计算得出钕的最佳添加量(质量分数)约为4.3%。     

Iron‐Rich Iron‐Titanium‐Silicon Alloys with Strengthening Intermetallic Laves Phase Precipitates

Two‐phase ternary Fe‐Ti‐Si alloys with Si contents from 2 to 16 at.% and Ti contents from 2 to 28 at.% were studied with respect to room temperature hardness, fracture strain and yield stress at room and higher temperatures up to 1150 °C. In addition oxidation was checked at temperatures between 400 and 1150 °C. The alloys are strengthened by precipitation of the stable Laves phase (Fe,Si)₂Ti which is a hard and brittle intermetallic phase. The yield stress as well as the brittle‐to‐ductile transition temperature (BDTT) increase with increasing Ti content. Yield stresses up to about 1400 MPa and BDTT between 100 °C and 600 °C with fracture strains of the order of 1 % below BDTT were achieved. The observed short‐term oxidation performance at temperatures up to 1150 °C compares favourably with that of Fe‐AI alloys with high Al contents.     

WC含量对TiCN-HfN金属陶瓷刀具材料微观组织和力学性能的影响

采用热压烧结技术制备了TiCN-HfN-WC金属陶瓷刀具材料,研究了WC含量(质量分数)对金属陶瓷刀具材料微观组织和力学性能的影响。结果表明:TiCN-HfN-32%WC金属陶瓷刀具材料由TiCN、(Ti,Hf,W)(C,N)、WC和MoNi组成,材料中还含有极少量的(Ti,Mo,W)(C,N)固溶体,材料内部形成了网状骨架结构。随着添加WC质量分数的增加,材料中晶粒粒度降低,添加WC可抑制材料中TiCN晶粒的生长,起到细化TiCN晶粒的作用;材料的相对密度、硬度和断裂韧度都具有先增大后减小的变化趋势,材料的抗弯强度逐渐增大。当WC质量分数为32%时,材料具有相对较好的综合力学性能,其硬度为20.2 GPa,断裂韧度为7.1 MPa×m^1/2,抗弯强度为1581.3 MPa。     

Nb-Ti微合金化对热轧0.5~0.7Cr铲斗刀板型钢组织和性能的影响

试验0.5~0.7Cr铲斗刀板型钢（/%:0.22~0.30C,0.25~0.45Si,0.95~1.20Mn,0.006~0.009P,0.008~0.010S,0.5~0.7Cr,0.015~0.065Nb,0~0.040Ti）由50kg真空感应炉熔炼,热轧成16mm厚板,终轧温度850~900℃,空冷。通过光学显微镜、扫描、透射电镜和力学性能测试研究了Nb-Ti含量（0.015Nb,0.035Nb-0.010Ti,0.065Nb-0.040Ti）对热轧态铲斗刀板钢组织和力学性能的影响。结果表明,试验钢组织为F+P,随Nb-Ti含量增加,钢板的晶粒细化,珠光体片层间距降低,（Nb,Ti）C和（Nb,Ti）(C,N)析出物增多,强度增加,0.065Nb-0.040Ti钢板的力学性能为屈服强度632MPa,抗拉强度916MPa,延伸率17.7%,K_AV40 J,HB硬度值234。     

微米／纳米Ti（C,N）基金属陶瓷刀具材料的研制

系统研究了添加纳米级Al2O3的含量对Ti(C,N)基金属陶瓷力学性能和显微结构的影响。结果表明:纳米Al2O3的添加可大幅提高Ti(C,N)基金属陶瓷的力学性能,特别是硬度和断裂韧性明显提高,克服了Ti(C,N)基金属陶瓷硬度较低的缺点,扩大了其应用范围。通过对微观结构观察和分析,可以看出,纳米Al2O3的添加细化了基体的晶粒,主要断裂模式为穿晶断裂,晶粒的细化和断裂模式的改变是材料力学性能提高的主要原因。     

联合法海绵钛生产中主要杂质分析及其控制

论述了联合法海绵钛生产中主要杂质(Fe,Si,Cl,C,N,O)的来源、分布及其对产品质量的影响,对比分析了国内外海绵钛产品质量存在差异的原因,从原料(TiCl4、镁锭、氩气)、设备(反应器)、操作工艺(加料制度、散热体系)等方面分析了减少杂质含量的控制措施。     

铝硅系铸造铝合金的原位统计分布分析

The element distribution analysis for the Al-Si casting aluminum alloys has been done by metal original position analyzer(OPA). The quantitative distribution analysis results of Si, Fe, Cu, Mn and Ti have been obtained by selecting suitable spectrum reference materials and optimizing the instrumental parameters. The content results of five elements by OPA method have good coincidence with the values determined byspark source atomic emission spectrometer. The scanning analysis results show that the distribution of Si, Cu and Ti is homogeneous and some obvious segregation of Fe and Mn has been found in two real aluminum alloys and the content distributions of two elements are very similar. It can be concluded thatthere are some compound of Fe and Mn in casting aluminum alloys by the result of multi-element spectrum channel combination analysis. The conclusion also has good agreement with the results by scanning electron microscope and energy spectrum analysis.     

原始成分组成对Ti(C,N)基金属陶瓷烧结性能的影响

采用真空烧结工艺制备了Ti(C,N)基金属陶瓷,研究了原始成分组成对材料烧结特性和力学性能的影响规律。结果表明:保持Mo/(Mo+Ni)为定值,随着硬质相成分的增加,烧结体抗弯强度降低,硬度增加;硬质相成分TiN含量超过一定阈值时,烧结体疏松导致硬度和抗弯强度同时大幅下降;TiN含量保持定值,硬质相成分含量增加,烧结体硬度增加,抗弯强度下降;粘结相成分用Co部分替代Ni,随Co含量的增加,烧结体硬度略有升高的基础上抗弯强度升高。     

Study on the interface of direct hot rolling titanium-clad steel plates

In this study,the interface characteristics of a direct hot rolling titanium-clad steel plate were analyzed,and the mechanism of interface cracking was explored.The detrimental effect from the formation of TiFe,TiC,and a Si-enriched layer on the bonding strength was clarified,and an industrial-scaled titanium-clad steel plate with shear strength over 200 MPa was produced with a carefully set schedule accordingly.It was found that hot rolling titanium-clad steel plates had a flat interface without obvious cracks.In the rolling process,both Ti and Fe atoms interdiffused,but Fe diffused much faster than Ti.The Fe-diffused area consisted of three regions.After a high temperature heat treatment,the diffusion depth of Fe and Ti elements increased significantly and evident Si segregation and TiFe layers were identified.Thermal cracking initiated in the Si segregation layer and then propagated along the TiFe layer and Fe-diffused layer on the titanium side.     

Effect of Rare Earths on Mechanical Properties and Microstructures of Si3N4-based Ceramics

Si3N4-hased ceramics exhibit excellentproperties such as high strength, high corro..sion resistance, high fire resisting property andhigh thermal shock resistance. However, up tonow, the application of St3N4-based ceramicsis still limited by their poor ductility, lowtoughness and stability. Adding fiber or whisher into ceramic matrix is a useful tougheningmethod, but fiber and whisker are costly and itis difficult to homogenize them in ceramic matrix. Furthermore, ceramic powders can not fill…     

不同含量复式碳化物对细晶硬质合金性能的影响

选取含TiC和TaC的复式碳化物,采用真空烧结,分别制备含复式碳化物0、4%、8%、12%的细晶WC-8Co硬质合金。研究不同含量的复式碳化物对细晶硬质合金横向断裂强度、硬度、相对密度的影响。实验结果表明,复式碳化物的添加能够提高硬质合金的硬度,但同时降低了合金的横向断裂强度和相对密度。当添加复式碳化物12%时,合金的横向断裂强度为1 480 MPa,硬度为93.6 HRA,相对密度为99.2%。