Effect Multiple Addition (TiO2 and Fly Ash) on Wear Behavior and Hardness of 2024 Al Alloy

This research is devoted to study the effect of addition (2%) TiO2 with different weight percent of fly ash particulate (0, 2, 4, 6%) to 2024 Al alloy on the wear behavior and hardness. The alloy was fabricated by the liquid metallurgy method. The results founds that the wear rate decreased from 0.55 with 0% fly ash to 0.18 at addition percentage of 6% fly ash. Also, the results reveal increasing the samples wear rate with increasing the load and loaded time. The rate of wear was decreased with increasing the sliding speed. Also, the values of hardness increased from 120VH to 160VH with rising the fly ash from 0% to 6%. Keywords: Fly Ash addition, TiO2, 2024 Al Alloy, Wear Resistance, Hardness.

MAT-free Reflection Arrangements

We introduce the class of MAT-free hyperplane arrangements which is based on the Multiple Addition Theorem by Abe, Barakat, Cuntz, Hoge, and Terao. We also investigate the closely related class of MAT2-free arrangements based on a recent generalization of the Multiple Addition Theorem by Abe and Terao. We give classifications of the irreducible complex reflection arrangements which are MAT-free respectively MAT2-free. Furthermore, we ask some questions concerning relations to other classes of free arrangements.

Effects of Ni and Co Additions to Filler Metals on Ag-Brazed Joints of Cemented Carbide and Martensitic Stainless Steel

This study focuses on understanding the effect of Ni and Co additions to filler metals on Ag-brazed joints of cemented carbide and martensitic stainless steel. Ni and Co added braze alloys were processed based on Ag-Cu-Zn ternary alloy, and joint strength and microstructure of the brazed layer has been investigated. The joint strength increased by the 2.0mass%Ni and 0.5mass%Co addition into braze alloy. This trend is remarkable in the Co added alloy, and the brazed joint increased by 141% compared to that in no-added alloy. The joint strength was closely related to the suppression effect of Co dissolution from cemented carbide into filler layer and Fe diffusion from the stainless steel to the brazed layer. In the brazed microstructure, Co-depleted zone caused by dissolution of Co in the cemented carbide was observed near the interface between the cemented carbide and the steel. Width of the Co-depleted zone significantly decreased in the Co added alloy. However, the joint strength decreased in the multiple addition compared to that in the single addition of Ni or Co.