Coherency loss of Al3(Sc,Zr) precipitates by deformation of an Al–Zn–Mg alloy
Coherency loss of Al3(Sc,Zr) precipitates by deformation of an Al–Zn–Mg alloy
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DOI：
10.1016/j.actamat.2012.04.011
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发表时间：
2012-06
期刊：
影响因子：
9.4
通讯作者：
M. Schöbel;P. Pongratz;H. Degischer
中科院分区：
文献类型：
--
作者：
M. Schöbel;P. Pongratz;H. Degischer
添加Sc和/或Zr的Al合金由于在>300°C的温度下形成的共格Al 3（Sc，Zr）沉淀物的均匀分布而表现出相当稳定的晶粒结构。这些沉淀物在固溶处理温度下是稳定的，并且能够钉扎亚晶粒和晶界，抑制晶粒粗化。这些沉淀物的晶体结构呈现与面心立方Al基体共格的L12超结构。描述了AW 7010（AlZn 6 Mg 2Cu 2）挤压变形、恢复和部分再结晶试样中析出相与基体之间取向关系的变化。在挤出物中存在的晶内Al 3（Sc，Zr）沉淀物的相干性通过由等通道角挤压工艺执行的严重变形而丧失，所述等通道角挤压工艺产生细晶粒显微组织。变形的样品恢复，形成亚晶粒结构与恢复的连贯性的Al 3（Sc，Zr）沉淀。快速加热到470°C会导致部分二次再结晶，这会将再结晶晶粒内的沉淀物转化为不相干的颗粒群，这些颗粒群彼此保持其原始取向。
Al alloys with additions of Sc and/or Zr exhibit a reasonably stable grain structure due to a uniform distribution of coherent Al3(Sc,Zr) precipitates that forms at temperatures >300°C. These precipitates are stable up to the solution treatment temperature and are able to pin subgrain and grain boundaries, inhibiting grain coarsening. The crystallographic structure of these precipitates presents a L12superstructure coherent with the face-centred cubic Al matrix. Changes in the orientation relation between precipitates and the matrix are described in deformed, recovered and partially recrystallized samples of extrusions of AW7010 (AlZn6Mg2Cu2). The coherency of the intracrystalline Al3(Sc,Zr) precipitates present in the extrusions is lost by severe deformation performed by an equal channel angular pressing process, which produced a fine-grained microstructure. The deformed sample recovers, forming a subgrain structure with restored coherency of the Al3(Sc,Zr) precipitates. Rapid heating to 470°C causes partial secondary recrystallization, which transforms the precipitates within the recrystallized grains into incoherent groups of particles that maintain their original orientation with each other.