机械合金化制备的Al基轴承合金的结构与性能

采用机械合金化方法制备Al-Pb和Al-Sn基合金粉末,然后通过烧结将之制备成合金.采用XRD、SEM、TEM分析技术对合金的微观结构进行表征,结果表明在适当机械合金化和烧结工艺条件下,可得到Al基体上均匀分布尺寸约为100nm的软相Pb或Sn的合金.摩擦摩损性能测试表明,这种组织结构的Al基轴承合金具有优良的性能.对Pb相粗化的研究表明,这种纳米复合结构具有较好的稳定性,其第二相的长大仍然满足关于粗化的经典理论——LSW理论.研究中还特别关注了机械合金化过程中的污染对Al基轴承合金组织结构的影响,发现铁污染会导致Al7Cu2Fe相的生成,氧污染则导致Pb颗粒上有Al2O3附着.

Microstructure and Wear Properties of Al-Based Bearing Alloys Fabricated by Mechanical Alloying

Al-Pb and Al-Sn bearing alloys were obtained by sintering the Al-Pb and Al-Sn powder mixtures prepared via mechanical alloying.According to the microstructures of the alloys characterized by means of XRD,SEM and TEM,the Pb or Sn soft phase in a size of about 100nm homogeneously disperses in Al matrix of the alloys fabricated under appropriate mechanical alloying and sintering conditions.It is indicated by the wear test that the Al-based bearing alloys containing nano-sized Pb or Sn dispersoids are of excellent wear properties.Moreover,according to the coarsening behavior of the nanophase particles,the nano-composite structure possesses good stability and the growth of the second phase still follows the classical ripening theory described by LSW equation.As for the effect of the contamination induced by milling on the microstructure of Al-based bearing alloys,the Al7Cu2Fe phase forms owing to the Fe contamination,and the adherence of nano-sized Al2O3 phase to Pb particles occurs due to the oxygen contamination.