通过对镍基合金的焊接性进行分析, 确定了大口径镍基复合管的焊接工艺, 采用背部充氩的钨极氩弧自动焊进行根焊、气体保护自动焊进行填充盖面的自动焊焊接工艺, 并且对焊接接头进行了常规力学性能、过渡层化学成分、显微硬度进行了研究.结果表明: 该焊接工艺切实可行, 焊缝成分能保证复合管焊接过程中的力学要求.

Crosslinked nitrile rubber (NBR) /hindered phenol (AO-80) /carbon black composites were prepared by mixing AO-80 and carbon black into NBR with different bound acrylonitrile contents. The thermal properties, dynamic mechanical properties and mechanical properties of the composites were characterized by differential scanning calorimetry, dynamic mechanical analysis and tensile tester. The results showed that compared with pure NBR, the glass transition temperature of NBR/AO-80/carbon black composites increased greatly, and shifted to high temperature direction with increasing the bound acrylonitrile content of NBR. NBR/AO-80/carbon black composites showed excellent damping properties: loss factor (tan δ) was more than 1.22, and the effective damping temperature range (tan δ equal to or more than 0.3) was more than 38℃, the frequency range with high tan δ was wide at different reference temperatures. NBR/AO-80/carbon black composites had good mechanical properties and thermal aging resistance. Especially, N 220 S/AO-80/carbon black composites were the best in all-round properties.

By controlling the migration of chemical reaction and diffusion of sulfur concentration in the rubber matrix to form sulfur distribution gradient,gradient polymer with wide damping temperature range was prepared.The results showed that,the glass transition range of SBR gradient polymer was over 100 ℃,and the peak width at half height was 69.44 ℃;the glass transition range of NBR gradient polymer was over 120 ℃,and the half width was 59.4 ℃.

The purification treatment and surface modification for carbon nanotubes(CNTs)were introduced.The preparation methods of CNTs/rubber composites including mechanical mixing,solution blending,spray drying and the performances such as mechanical properties,electrical conductivity,thermal conductivity were reviewed in detail with 45 references.The directions for further researches were proposed and discussed based on the analysis of property shortage of composites.