ZL201合金的半固态成形组织和力学性能

Microstructure and mechanics property of ZL201 alloy obtained by semi-solid forming

制备ZL201合金半固态坯料、将其二次加热、触变模锻成形以及成形件热处理,研究了工艺条件对成形件的组织和力学性能的影响．结果表明:采用近液相线半连续铸造技术制备的ZL201合金半固态坯料微观组织为大量细小的等轴晶和少量短程枝晶;在适当的工艺条件(在640℃保温5 min,模具温度250～300℃,留模时间10～15 s)下可触变成形出表面光洁的ZL201合金成形件;经过T5处理后,ZL201合金的抗拉强度达到278 MPa,延伸率达到9％,大大高于压铸成形件的性能,其强化相为CuAl2和TiAl3．由于成形速度高,溶体高速充型,造成成形件气孔率高,使ZL201合金半固态压铸成形的组织致密度不如半固态模锻成形件,这是半固态压铸件强度低、模锻件强度高的主要原因．

The microstructures and properties of solution agied ZL201 alloy prepared by nearliquidus semi-countinuous casting followed by thixoforging by means of electron microscope and electron pull machine were investigated. The results show that the fine and uniform equiaxed grains structure can be obtained. The optimal crafts parameters of semi-solid die-forging for ZL201 are： slurry temperature 640 ℃, die temperature 250-300 T3, holding time in die 10-15 s. Measurements yield following mechanical properties after T5 treatment： σb=278 MPa, 65=9%. The strengthening phase is CuAl2 and TiAl3. It is because quickly forming speed, highly pore content and low structure density that the intensity of the die-casting is lower than that of the forging.