锰对ZA27合金压蠕变行为的影响

Effect of Mn on Compressive Creep Behavior of ZA27 Alloy

采用自制的实验装置研究了锰对 ZA2 7合金在常温及高温时的压蠕变行为的影响。研究表明 ,在所试验的温度为 2 0℃到 16 0℃和压应力为 5 0 MPa到 137.5 MPa的范围内 ,加入锰的合金 ZA2 7- Mn和未加锰的 ZA2 7合金的压蠕变量均随着温度和应力的升高而增大 ,ZA2 7- Mn合金的压蠕变速率小于 ZA2 7合金的压蠕变速率。加入锰后 ,合金在压蠕变过程中的负蠕变量及出现负蠕变的温度和应力范围增大。两种合金的稳态蠕变速率均符合于半经验公式 εs=Aσnexp(- Qa/RT)。但在不同的温度 ,ZA2 7- Mn合金的应力指数 n和表观激活能 Qa 均大于 ZA2 7合金的应力指数和表观激活能 ,而 ZA2 7- Mn合金的材料结构常数 A为 1.5 4× 10 - 4,低于 ZA2 7合金的材料结构常数 A(0 .0 0 2 )。两种合金的稳态蠕变速率均是由锌的点阵自扩散和位错的攀移所控制。

The effect of Mn on compressive creep behavior of an as-cast ZA27 alloy was investigated at room and high temperature in the range 20℃～160℃ and different compressive stress in the range 50 MPa～137.5 MPa with a special apparatus.The results show that compressive creep deformations of ZA27-Mn alloy and ZA27 alloy increased with temperature and compressive stress,and the steady creep rate of ZA27-Mn alloy was lower than that of ZA27 alloy.The negative creep deformations during compressive creep and the range of temperature and stress at which negative creep occurred increased after adding some Mn to ZA27 alloy.The steady creep rates of ZA27-Mn alloy and ZA27 alloy could obeyed an empirical equation =Aσ n exp (-Q a/RT).Compared with ZA27 alloy,the stress exponent n and appearance activation energy Q a of ZA27-Mn alloy were greater.However,materials constant A of ZA27-Mn alloy and ZA27 alloys was 1.54×10 -4 and 0.002,respectively.It was considered that the steady creep rates in ZA27-Mn and ZA27 experimental alloy were controlled by lattice diffusion in zinc and by a dislocation limb.