Dislocations: 75 years of Deformation Mechanisms

The selection of papers presented in this section reflect on themes to be explored at the "Dislocations: 75 years of Deformation Mechanisms" Symposium to be held at the Annual 2009 TMS meeting. The symposium was sponsored by the Mechanical Behavior of Materials Committee to give tribute to the evolution of a concept that has formed the basis of our mechanistic understanding of how crystalline solids plastically deform and how they fail

Advances in Solid State Joining of Haynes 230 High Temperature Alloy

The J-2X engine is being designed for NASA s new class of crew and launch vehicles, the Ares I and Ares V. The J-2X is a LOX/Hydrogen upper stage engine with 294,000 lbs of thrust and a minimum Isp of 448 seconds. As part of the design criteria to meet the performance requirements a large film-cooled nozzle extension is being designed to further expand the hot gases and increases the specific impulse. The nozzle extension is designed using Haynes 230, a nickel-chromium-tungsten-molybdenum superalloy. The alloy was selected for its high strength at elevated temperatures and resistance to hydrogen embrittlement. The nozzle extension is manufactured from Haynes 230 plate spun-forged to form the contour and chemically-milled pockets for weight reduction. Currently fusion welding is being evaluated for joining the panels which are then mechanically etched and thinned to required dimensions for the nozzle extension blank. This blank is then spun formed into the parabolic geometry required for the nozzle. After forming the nozzle extension, weight reduction pockets are chemically milled into the nozzle. Fusion welding of Haynes results in columnar grains which are prone to hot cracking during forming processes. This restricts the ability to use spin forging to produce the nozzle contour. Solid state joining processes are being pursued as an alternative process to produce a structure more amenable to spin forming. Solid state processes have been shown to produce a refined grain structure within the joint regions as illustrated in Figure 1. Solid state joining processes include friction stir welding (FSW) and a patented modification termed thermal stir welding (TSW). The configuration of TSWing utilizes an induction coil to preheat the material minimizing the burden on the weld tool extending its life. This provides the ability to precisely select and control the temperature. The work presented in this presentation investigates the feasibility of joining the Haynes 230 alloy using the solid state welding processes of FSW and TSW. Process descriptions and attributes of each weld process will be presented. Weld process set-up and welding techniques will be discussed leading to the challenges experienced in joining the superalloy. Mechanical property data will also be presented

House Rules Manual: Summary of Contents

This report briefly discusses The House Rules and Manual, officially titled Constitution, Jefferson’s Manual and Rules of the House of Representatives, which contains the fundamental source material describing procedures in the House of Representatives

Advances in Solid State Joining of High Temperature Alloys

Many of the metals used in the oil and gas industry are difficult to fusion weld including titanium and its alloys. Thus solid state joining processes, such as friction stir welding (FSWing) and a patented modification termed thermal stir welding (TSWing), are being pursued as alternatives to produce robust structures more amenable to high pressure applications. Unlike the FSWing process where the tool is used to heat the workpiece, TSWing utilizes an induction coil to preheat the material prior to stirring thus minimizing the burden on the weld tool and thereby extending its life. This study reports on the initial results of using a hybrid (H)-TSW process to join commercially pure, 1.3cm thick panels of titanium (CP Ti) Grade 2

Legislative Planning: Considerations for Congressional Staff

This report presents some of the factors usually considered in preparing a legislative or office action plan. The information is provided in three sections: (1) an overview which lays out summary consideration, (2) questions to consider in preparing an outline for a project, and (3) a sample action plan

House Committees: Categories and Rules for Committee Assignments

This report provides an overview of the categories and rules for committee assignments

House Leadership: Whip Organization

This repor

House Committees: Categories and Rules for Committee Assignments

This report House and party rules, both of which detail procedures for committee assignments. House rules address the election and membership of committees, especially limitations on membership. The Democratic Caucus and Republican Conference rules designate categories of committees (shown below) and specify service limitations in addition to those in the House rules