莫来石短纤维增强铝基复合材料拉伸强度数据韦伯统计分析(英文)

Weibull Statistical Analysis of Tensile Strength Data of Mullite-short-fibre-reinforced Aluminium Alloy Composite

用挤压铸造工艺得到了拉伸强度比较高并且强度数据分散度比较小的莫来石纤维/ZL109复合材料。用Weibull方法分析该复合材料的拉伸强度值的分布状况,得到比较大的Weibull模量。统计分析了复合材料金相面上的纤维体积分数和拉伸断口面上的纤维体积分数,结果表明,纤维的分布在微观上是不一致的;在金相面上,与观察法线呈中角度的纤维体积分数Afs同与观察法法线成大角度的纤维体积分数Af1比较接近;在拉伸断口面上与拉伸方向呈大角度的纤维体积分数同与拉伸方向呈小角度的纤维体积分数相差较大。认为该复合材料破坏的主要原因是在于与拉伸方向呈大角度的纤维与基体的界面脱粘。拉伸强度数据分散的原因在于微观上与拉伸方面呈大角度的纤维分布的不均匀。

This paper presents a statistical evaluation by means of Weibull statistics of the tensile strength of a mullite-short-fibre-reinforced aluminium alloy composite,which was prepared by squeeze casting.The results show the material has a high and reliable tensile strength.The area fractions of the fibres on the cut surface and on the fracture surface of samples have been statistically analyzed.The fibre distribution shows a heterogeneity in the microstructure.On the cut surface the average area fraction of fibres which make large angle with the normal of cut surface(denoted as A_(f1)),is slightly less than that of those fibres which make a small angles with the normal of the cut surface(denoted as A_(fs)).However,on the fracture surface of the composite,A_(f1)is much bigger than A_(fs).And the lower the tensile strength of the specimen,the bigger is A_(f1) on the fracture surface.Debonding of the interface between the large-angle-fibres and the matrix is an important cause of the failure of the composite,and the non-uniform distribution of the large-angle-fibres is one of the main causes of the data scattering over a large range.