大变形热轧工艺对建筑用KK1铝青铜的组织与力学性能的影响

Influences of large deformation hot rolling process on microstructure and mechanical properties of KK1 aluminum bronze for construction

选择KK1铝青铜作为测试材料,分析合金经过大变形热轧与时效处理后发生的组织结构及力学性能的改变。研究结果表明:当热轧比例达到70%时,原有的等轴状α相与β相组织转变为尺寸非常细小的片层状结构,从而获得了非常细小的合金组织,经过热轧处理后,试样组织中形成了析出相;在380℃下,时效组织在片层状的细小β相间形成了模糊界面,模糊界面属于(α+β)相构成的双相片层组织。KK1铝青铜组织内均存在α相、β相,同时还有部分k相。经过热轧和时效处理的试样形成了相近的衍射峰,可见时效过程并不会改变铝青铜的组织结构。KK1铝青铜在热轧变形后,表面硬度明显增大,拉伸强度也增大至1095 MPa,各项性能均得到了改善。相比时效试样,热轧铝青铜达到了更高的应变硬化速率。

For KK1 aluminum bronze,the changes of microstructure and mechanical properties for alloy after large deformation hot rolling and aging treatment were analyzed.The results show that when the proportion of hot rolling reaches 70%,the original isometricαandβphases are transformed into very fine lamellar structures to obtain very fine alloy structure.After hot rolling treatment,the precipitated phase is formed in the sample structure.Then,at the temperature of 380℃,the aging structure forms a fuzzy interface between lamellar and fineβphases,which belongs to double-phase layer structure composed of(α+β)phase.However,in the microstructure of KK1 aluminum bronze,there areαandβphases and some k phases,and after hot rolling and aging treatment,the sample forms a similar diffraction peak.Thus,the aging process cannot change the structure of aluminum bronze.Furthermore,after the hot rolling deformation of KK1 aluminum bronze,the surface hardness increases significantly,the tensile strength also increases to 1095 MPa,and all the properties are improved.Finally,compared with aged sample,the hot rolled aluminum bronze achieves a higher strain hardening rate.