中文摘要：

研究了TC4钛合金在不同保温温度和冷却速度下热处理后的显微组织及硬度。结果表明,在970℃保温冷却后,由于温度稍低于相转变温度,α相并没有完全转变为β相,冷却后的组织仍有初生α相。在1020℃以上加热保温后,炉冷和空冷时由于冷却速度较慢,转变生成的α相比较粗短且排列紧密,冷却速度越慢α相越粗大;油冷和水冷下主要获得片状和针状马氏体组织。TC4钛合金的硬度随着冷速的增加而增加,但增加幅度不大。在1020℃以上保温时,温度对硬度没有明显的影响。

英文摘要：

Microstructure and hardness of TC 4 titanium alloy were studied under different heating temperature and cooling rate .The results show that heated at 970℃, because the temperature slightly lower than the phase transition temperature ,αphase does not entirely transform intoβphase, the primary αphase still exists after cooling .When the heat temperature is above 1020 ℃, due to the slower cooling rate of furnace cooling and air cooling , theαphase presents stubby and closely packed , the slower the cooling rate , theαphase is more coarse , and the plate and acicular martensite structure are obtained under oil cooling and water cooling .The hardness of TC4 titanium alloy slightly increases with the increase of cooling rate .The influence of heat temperature on the hardness is not obvious when the heat temperature is above 1020 ℃.