直线截点法测定金属平均晶粒度的不确定度评定

采用直线截点法对某金属晶粒的平均截距进行了测量,并对测量过程中的每个不确定度分量进行了评定,然后根据不确定度传播规律求出了平均晶粒度的合成标准不确定度,并最终给出了扩展不确定度。结果表明:在该试验条件下,试验金属平均晶粒度测定的扩展不确定度U=0.1,包含因子k=2,平均晶粒度级别数G=8.4±0.1;该次评定测量不确定度较小与所测金属晶粒大小均匀、晶界清晰、仪器状态良好、检测人员水平接近、直线截点法本身的测定精度较高等因素有关,试验过程中要注意这些因素的控制。

12Cr2Mo1R钢带极堆焊镍基276的工艺性能

对不同堆焊工艺及不同热处理工艺下,12Cr2Mo1R钢板上带极堆焊镍基276(NiCrMo-4钢)的化学成分、晶间腐蚀性能、力学性能、显微组织等进行了分析,研究了镍基276的最佳堆焊工艺及热处理工艺。结果表明:先在12Cr2Mo1R钢板上堆焊309L钢(过渡层)/NiCrMo-3钢(中间层),然后对其进行(690±14)℃,32 h的模拟焊后热处理,最后堆焊表层镍基276,可以使钢板获得较低的腐蚀速率、较好的力学性能和显微组织。

Preparation and shape memory properties of TiO_2/PLCL biodegradable polymer nanocomposites

The preparation of TiO2/poly（L-lactide-co-ε-caprolactone）（PLCL） nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone（ε-CL）.The resulting poly（ε-caprolactone）-grafted TiO2（g-TiO2） was characterized by Fourier transform infrared spectroscopy（FTIR）,thermogravimetric analysis（TGA） and transmission electron microscopy（TEM）.The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained：an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.

ICP光谱法测量低合金钢CM-A106HD中V含量的不确定度评定

钢中添加V可以提高钢的强度,改善钢的韧性和塑性,改善钢的工艺性能,提高V钢制品的服役性能。此外,钢在使用过程中要经常进行焊接,焊接接头尤其是热影响区是最薄弱的环节,此处加入微量的V,可提高钢的强度,通过细化晶粒,抑制晶粒长大,同时提高其淬硬性,且能提高钢的高温性能。但V元素的加入也容易生成难熔氧化物,从而恶化焊接性能,因此,要对其含量加以控制。