凝胶浇注法制备Ti-6Al-4V合金坯体及坯体性能的研究

将凝胶浇注工艺应用于金属Ti-6Al-4V合金粉末的成形,研究了高固相含量的Ti-6Al-4V合金粉末料浆的制备和坯体的抗弯强度.结果表明,料浆固相含量随粉末的松装密度和分散剂的增加而增加.坯体的抗弯强度随气雾化(GA)Ti-6Al-4V含量增加先增大后减小,随着坯体的固相含量增大而减小.当GA-Ti-6Al-4V的质量分数为80%、固相含量为50%(体积分数)时,坯体的抗弯强度最大,为18.5MPa.     

凝胶注模法制备复杂形状钨铜复合材料

利用非水基体系凝胶注模法制备了复杂形状钨铜复合材料坯体。研究了分散剂含量以及固相含量对钨铜浆料黏度的影响,绘制了坯体的室温干燥曲线并制订了干燥制度,同时对坯体微观形貌、抗弯强度等进行了表征和测试。结果表明:分散剂添加量为0.15%(质量分数,基于金属粉末质量)时浆料黏度达到最低,在此基础上浆料的固相含量可达到45%(体积分数),满足凝胶注模的要求;坯体先在室温下干燥10h后放入100℃的恒温干燥箱中干燥8h,可得到表面无变形、无开裂的钨铜坯体;随着固相含量的增大,坯体致密性和均匀性均随之提高;坯体表面质量较好,抗弯强度可达到26.9 MPa。     

料浆刷涂针刺法制备C_f/C-ZrB_2复合材料及其力学性能

以天然石墨粉、ZrB_2粉末、醇溶性酚醛树脂粉末及炭纤维毡、炭纤维无纬布为原料,采用料浆刷涂、针刺、温压固化、高温碳化工艺,结合化学气相沉积工艺,制备C_f/C-ZrB_2复合材料。通过阿基米德排水法测试密度及孔隙率,采用扫描电镜分析及力学性能测试等手段,研究料浆固含量对C_f/C-ZrB_2多孔坯体中基体粉末分布的影响,以及对C_f/C-ZrB_2复合材料力学性能的影响。结果表明:料浆固含量增加,坯体中基体粉末分布的均匀性提高,材料力学性能随浆料固含量的增加呈现先升后降的趋势,当料浆固相体积分数为15%时,材料抗弯强度达到121.86 MPa。     

倾斜角度对激光选区熔化成形Ti6Al4V合金的影响

利用自主研发的Di Metal-100型激光选区熔化设备制备与基板平面成不同倾斜角的Ti6Al4V非标准拉伸试样,研究熔化成形后合金的显微组织、物理和力学性能。结果表明,Ti6Al4V合金粉末熔化成形后的组织为针状α′马氏体和(α+β)相,随倾斜角度变化,试样中α/α′相与β相的相对含量也发生变化,倾斜角为45°试样中β相含量最高;α′马氏体呈柱状分布于(α+β)相中,并且方向始终平行于成形方向(Z轴方向)。随SLM成形试样的倾斜角从0°增加到90°,其相对密度先减小后增大,并在90°时达到最大值96.1%;试样的硬度和抗拉强度均先升高后降低,在45°时达到最大值,硬度为393 HV,抗拉强度为1 288 MPa;试样表面粗糙度Ra也呈先增大后减小的趋势,在0°时达到最小值8.77μm,在30°时达到最大值19.55μm。     

非水基凝胶注模成形制备Mo/Cu合金

以球形铜粉和等离子球化钼粉为原料,采用非水基凝胶注模体系制备Mo/Cu合金.研究分散剂用量和固相体积分数对浆料黏度的影响,并对凝胶生坯的干燥、脱脂和烧结进行分析.结果表明:浆料黏度随着分散剂用量的增加先减小后增大,随着固相体积分数的升高而增大.采用丙酮作为液体干燥介质,6 h即可完全脱除凝胶坯体中的残留溶剂.烧结体的致密度随着烧结温度和烧结时间的升高而增大.      

反应烧结碳化硼低压注射成型用浆料粘度的研究

针对反应烧结B_4C陶瓷材料低压注射成型用浆料的制备问题,研究了颗粒级配、分散剂含量(质量分数)和B_4C固含量对浆料粘度的影响.研究结果表明:当B_4C粉体颗粒级质量比为m_((F320))∶m_((F800))=6∶4,分散剂质量分数为1%,B_4C固含量(质量分数)为80%时,浆料的粘度适合于低压注射成型,低压注射成型坯体中B_4C颗粒分散均匀,坯体的体积密度为1.79 g/cm~3,气孔率为2.07%,脱蜡坯体显微结构较为均匀.脱蜡坯体经过1550℃渗Si烧结后,材料的抗弯强度、断裂韧性、维氏硬度分别可达322.7 MPa、3.33 MPa·m~(1/2)、25.7 GPa.本实验通过控制颗粒级配,分散剂含量及B_4C固含量实现了低粘度、高固含量B_4C(w(B_4C)=80%)浆料的制备,并有效地提高了脱蜡坯体和反应烧结B_4C复合材料的性能.     

3D冷打印钨镍铁合金零件的研究

以军标钨粉、镍粉和铁粉为原料,利用3D冷打印技术制备90W-Ni-Fe合金零件。研究了粘结剂含量和固相含量对金属浆料粘度的影响,并对素坯的组织均匀性进行分析;通过TG-DTA曲线对脱脂烧结工艺进行优化,并分析了烧结体的形貌、金相组织和密度。结果表明:粘结剂添加量为4%、固相含量为70%～75%的W-Ni-Fe浆料,最适合3D冷打印;素坯垂直方向组织均匀性较好,金属颗粒较为均匀地填充在PVB构成的三维网状结构中,固相颗粒分布均匀且无明显的沉降现象;打印过程中,素坯厚度非线性增长,宽度不稳定,浆料固化速度仍有待提高。素坯脱脂后在1 440℃下烧结2h,获得密度为16.26g/cm~3的烧结体,致密度高达94.83%。     

热处理对选区激光熔化Ti6Al4V合金力学性能和耐磨性的影响

系统研究了热处理工艺对选区激光熔化Ti6Al4V合金组织、力学性能和耐磨性的影响。结果表明,沉积态样品组织以针状α’马氏体为主,经固溶处理后,针状α’马氏体分解,Ti6Al4V合金硬度下降。当固溶温度为800℃时,合金形成α’/α结构,其抗拉强度和延伸率分别增加12%和23%。当固溶温度达到900℃以上时,由于α’/α结构的消失、α相晶粒的粗化以及β相含量的增加,合金的力学性能急剧下降,抗拉强度从（935±10）MPa下降到（815±9）MPa,伸长率从（8.72±0.2）%下降到（3.09±0.1）%。随着固溶温度的升高,摩擦系数和磨损率线性增大,与硬度的变化趋势完全相反,且磨损机理由单一磨粒磨损转变为磨粒磨损和氧化磨损。     

EIGA雾化法制备3D打印用Ti6Al4V合金粉末

根据3D打印技术对金属粉末的特性要求,采用真空电极感应熔化气雾化法(EIGA)制备了Ti6Al4V合金粉末,研究了不同气雾化压力对粉末化学成分、粒径分布、颗粒形貌、流动性能的影响。结果表明:EIGA雾化法制备的Ti6Al4V合金粉末的氧增量小于0.02%(质量分数),雾化过程中会形成一部分"卫星球","空心粉"颗粒。随着雾化压力的升高,粉末的平均粒径逐渐减小,流动性能变差。根据3D打印技术对粉末性能的要求,雾化压力控制在3.2~3.6 MPa为宜。     

凝胶离心成形制备TiC-FeCrMo硬质合金

将凝胶离心成形工艺应用于TiC-FeCrMo硬质合金的坯体成形,研究了固含量对TiC-FeCrMo复合粉末浆料的流变性的影响,分析了凝胶离心成形过程中压力和聚合速率的关系,并研究了离心转速对坯体和烧结体性能的影响。结果证明:HEMA凝胶体系对TiCFeCrMo复合粉末具有很好的分散性,以油酸作分散剂,制备稳定且流动性好的浆料的最佳固含量为55%(体积分数),凝胶离心成形过程中压力能够加速浆料的固化,采用自行设计的离心成形机,选择最佳转速2 000r/min,制备出大尺寸棒状钢结合金坯体,坯体密度高、无残留气孔,强度高达30MPa,密度为4.07g/cm3,坯体经过真空脱胶烧结一体化烧结,1 420℃保温1h制备出钢结硬质合金烧结体,其密度为6.52g/cm3,抗弯强度1 580MPa。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.