TA15钛合金大规格中厚板残余应力的精确测定

Accurate Test of TA15 Titanium Alloy Hot-Rolled Plate with a Large Size and Middle Thickness

通过X射线对TA15钛合金大规格中厚度板材试样的(213)晶面进行扫描,观察其峰形变化,并采用sin2?法进行计算,得到残余应力值。在板材表面的一些位置残余应力出现较大偏差,使得测试结果不可靠。在30o?85o范围内对试样进行衍射扫描的基础上,认为粗晶是造成残余应力测定偏差大的原因,提出加大X射线照射面积的方法,准确测定残余应力。结果表明:TA15钛合金中厚板材热轧制后,表面存在着较大的残余压应力,范围在–250?–450 MPa之间,测量偏差均在±50 MPa以内。进一步分析了TA15钛合金热轧板材残余应力的形成机制,为消除残余应力提供理论基础和试验数据。

The residual stress was measured by X-ray diffractometer for large-size and middle-thick TA15 Ti alloy plate.By scanning the(213) plane of TA15 titanium alloy by X-ray diffraction,we observed the changes in peak shape,and used the sin2? method to calculate the residual stress.Residual stresses of some locations on the plate surface had large deviations under the normal diffraction conditions,so that the test results are not reliable.On the basis of the range 30°~85° diffraction scans on samples,it is regarded that big deviation of stress is resulted from the coarse grain.So we proposed that increasing the X-ray irradiating area should be an appropriate way to decrease the deviation of the residual stress.After improvement,the results show that the surface of TA15 titanium alloy plate possesses large compressive stress after hot rolling.The surface residual stress range is from –250 to –450 MPa,and measured deviations are within ±50 MPa,which is highly reliable.The further analysis of the formation mechanism was conducted on TA15 plate residual stress,providing a theoretical basis and experimental data to eliminate the residual stress.