(西安建筑科技大學 冶金工程學院， 西安 710055)
摘 要: 將等徑彎曲通道變形應用于7475鋁合金， 等效真應變達12。 對7475鋁合金在不同溫度下ECAP變形后顯微組織特征和晶粒細化極限進行了研究。 結果表明： 變形溫度從273K到773K， 7475鋁合金的晶粒細化極限為0.29 ~1.90μm，且極限晶粒尺寸的倒數與變形溫度的倒數成正比關系。 在較高溫度下， 組織中產生大量的沉淀相粒子能有效釘扎晶界， 阻礙晶粒長大， 使合金具有較好的組織熱穩(wěn)定性。
關鍵字: 7475鋁合金；等徑彎曲通道變形； 晶粒細化極限； 沉淀相粒子
（ School of Metallurgical Engineering,
Xi′an University of Architecture and Technology,
Xi′an 710055, China）
Abstract: Equal-channel angular pressing was conducted on a 7475 aluminum alloy at temperature from room temperature to 773K up to an equivalent true strain of 12. The grain refinement limit was dependent upon the precise pressing temperature, and the grain was refined to within the range from 0.29 to 1.9μm by ECAP at these different temperatures. At higher temperature, it is apparent that these precipitates may be important in pinning the grain boundaries and thus increasing the thermal stability of the sub-micrometer-grained structure.
Key words: aluminum 7475 alloy; equal-channel angular pressing; grain refinement limit; precipitate
