论文部分内容阅读
超塑性合金的结构敏感性很强,板材超塑性充模胀形的变形规律,不仅与应力状态有关,而且与加载路径有密切关系.超塑性自由胀形边界固定不受摩擦影响,因此,研究超塑性自由胀形的变形规律及其实验装置,是超塑性充模胀形成形的重要基础.采用纯净高压氩气源并用炉外加热系统加热后作为高温高压胀形加载介质,提高了热效率和试件加热的均匀性;采用光电转换非接触测量装置,避免了接触式顶杆对自由胀形件极点处附加应力和温度不均匀的影响;以筒形压边绝热炉内试件的温度和压力为依据,反馈调控温度和压力,提高了试件温度和压力的测控精度;在加载气路中通过准确测控步进电机转角实现调压,并控制电磁阀加载,显著增加了调控气压的响应特性.同时介绍了恒压加载、压力跃变加载以及附加背压的对向差压加载等几种自由胀形典型加载路径的实现步骤和方法,提供了测量超塑性自由胀形应变速率敏感性指数m值和探索提高超塑性自由胀形变形速度的新途径.
Superplastic alloys have strong structural sensitivities and the deformation laws of superplastic filling bulging of sheet are not only related to the stress state but also closely related to the loading path. The boundary of the superplastic free bulging boundary is not affected by the friction. Therefore, Superplastic free bulging deformation and its experimental device is an important foundation for superplastic filling inflation forming.Using a pure high-pressure argon source and heating with an external heating system as a high temperature and pressure bulging load medium to improve the thermal efficiency and The uniformity of the heating of the specimen; the use of photoelectric conversion non-contact measurement device to avoid the contactless mandrel on the free bulge pole additional stress and temperature unevenness; cylindrical blank holder insulation test furnace temperature and Pressure based on feedback temperature and pressure control to improve the measurement and control of temperature and pressure of the specimen precision; in the gas load by accurately measuring the stepper motor rotation angle to achieve pressure control, and control the solenoid valve load, significantly increased the response to the regulation of air pressure Characteristics.At the same time introduced the constant pressure load, pressure jump load and the additional back pressure on the differential pressure loading of several free bulging typical load path to achieve the steps The method provides a new way to measure the free bulging superplastic strain rate sensitivity value m and exploration improve superplastic free bulging deformation rate.