Al-Mn系合金的組織控制與高溫性能研究

Al-Mn系合金的組織控制與高溫性能研究MICROSTRUCTURE CONTROL AND HIGH TEMPERATURE PROPERTIES OF Al-Mn-BASED ALLOYS

研究了合金元素Mg、Ni和Zr以及退火工藝對Al-Mn系合金顯微組織和高溫性能的影響。結果表明：Al-Mn系合金經冷軋+873 K保溫10 min得到細小等軸晶，而冷軋+623 K保溫1 h+873 K保溫10 min可獲得有利于高溫性能的長條狀組織，提出了再結晶組織控制方法。合金元素Mg促進了熱處理過程中AlMnSi相的析出，合金元素Zr、Ni增加了彌散相的數量和種類，析出Al3Zr、 AlMnSiNi耐熱相。Mg和Ni聯合添加時高溫力學性能最優，523 K下抗拉強度達102 MPa（比Al-Mn合金提高104%），523 K/ 40 MPa條件下穩態蠕變速率為3.93×10-8 s-1，比Al-Mn合金低兩個數量級。得出等同條件下，基體長條狀程度越明顯，沉淀相數量和種類越多，高溫抗拉強度越高、蠕變性能越好。

Effect of Mg, Ni and Zr additions and annealing process on the microstructure and high temperature properties of Al-Mn-based alloys were investigated. The investigated alloys were treated in two ways, first one is cold-rolling and heat treatment at 873 K for 10 min, and the second one is cold-rolling, heat treatment at 623 K for 1 h and 873 K for 10 min. The results indicate that annealing process has remarkable effect on the grain shape, the former treatment could obtain the sample with fine equiaxed crystal grains, while stable elongated grains were obtained for precipitation precedes recrystallization at 623 K in the latter. With Mg addition, the number of AlMnSi phase were increased. The addition of Zr、Ni increased the type and amount of heat resistant compounds, precipitated Al3Zr and AlMnSiNi, which are beneficial to improve high temperature properties of Al-Mn alloy. Al-Mn-0.3Mg-0.2Ni alloy has the best elevated temperature properties, the tensile strength of it is 102 MPa (104% higher than Al-Mn alloy) at 523 K. And the steady-creep rate is strongly decreased to 3.93×10-8 s-1, two orders of magnitude smaller than Al-Mn alloy at the temperature of 523 K under the stress of 40 MPa. With the grain elongated and dispersoids complicated or increased, the tensile strength and creep resistance of Al-Mn alloy improved significantly.

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