等通道变形Al-Ti中间合金组织及细化效果_金属材料工程.rar

摘要：本文是以Al-Ti中间合金为研究对象，对其进行等通道变形（ECAP），研究不同道次变形对Al-Ti显微组织，电导率，显微硬度，以及作为细化剂对铝组织细化效果与性能的影响。研究结果表明：Al-Ti中间合金经ECAP剧烈塑性变形，细长针状Al3Ti相逐渐破碎、细化，并且均匀分布于铝基体上。Al-Ti中间合金ECAP变形后，电导率由铸态的33.62%IACS变为1道次后的27.93%IACS，2道次后的24.83% IACS，3道次后的23.45%IACS，电导率呈现为先降低而后平稳的趋势。显微硬度值也有显著增加，由铸态的40.1Hv变为1道次后的43.04Hv，2道次后的45.74Hv，3道次后的47.14Hv。添加ECAP变形Al-Ti中间合金到铝熔体中，可以释放细小的形核粒子，这些粒子促进了细小等轴晶的形成，使铸态铝中的柱状晶区减小，等轴晶区扩大且晶粒更加细小。因此，ECAP变形Al-Ti中间合金细化剂在工业铝合金组织细化方面有很大的应用潜力。

关键词：Al-Ti中间合金；ECAP变形；电导率；显微硬度；显微组织；细化效果

Abstract:Al-Ti Master alloys was subjected to equal channel angular pressing (ECAP) investigating microstructure,electrical conductivity，micro-hardness and refining efficiency of different passes. The results show that Al-Ti samples were subjected to severe plastic deformation by using the ECAP technique, Al3Ti phase on the cast gradually deforms and breaks, at last, the phase evenly distributes on the Al matrix.It is testified that the electrical conductivity is varied from 33.62%IACS as cast condition to 27.93%IACS for 1 pass, 24.83%IACS for 2 passes, 23.45%IACS for 3 passes. At the same time, the micro-hardness (Hv) value of Al-Ti refiner after ECAP processing has a significant increment than that of before ECAP processing.The hardness is varied from 40.1Hv as cast condition to 43.04Hv for 1 pass, 45.74Hv for 2 passes, 47.14Hv for 3 passes. The conductivity increases at first, and then becomes stable. The addition of Al-Ti system grain refiner to Al melt releases nucleant particles that promote equiaxed,which reduces columnar crystal zone,expends and refines equiaxed crystal zone of the aluminum tissues.It is concluded that the Al-Ti refiner with ECAP technique has a very useful practical application in refining industrial Al alloys.

Keywords：Al-Ti Master alloys;  ECAP;  electrical conductivity;  micro-hardness; microstructure;  refining effect